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Email Marketing Glossary

Email and online marketing terms and definitions might seem overwhelming for a newbie. Our email marketing glossary aims to help you out. It provides definitions for more than 100 email and online marketing terms. From A to Z, you’ll find concise, helpful definitions.

Even if you are a seasoned marketer, you will find out email marketing glossary useful. In email marketing, changes happen fast. If you want to be always up-to date, our glossary of common email terminology is a go-to place. We put together email and online marketing terms and definitions to make your life easy.

In order to skip ahead to certain areas, just click on the bolded letters at the top of the page.

Email Marketing Glossary: 123 Terms to Know



A/B Testing

Test several variants of your newsletter against one another. A small portion of your contact list will be sent one of the variants. The most successful variant will automatically be sent to the rest of your list. Multivariate A/B testing enables to test more than two variants.


Above the fold indicates the area of an email or website that can be viewed without scrolling. This area should contain the most important information in your email.

Alt Text

If an image in your newsletter can’t be displayed, the alt text will be displayed instead. The alt text should therefore be relevant to the image and your newsletter.

Animated GIF

You can use animated gifs to bring moving elements into your emails. In order to create a custom gif, you’ll need to use Java or Flash. Otherwise, there are lots of online tools that will help you, as well as tons of online gifs that you can “borrow”!


In computer programming, an application programming interface (API) is a set of routines, protocols, and tools for building software and applications. APIs are one of the most common ways technology companies integrate with each other. Those that provide and use APIs are considered as being members of a business ecosystem. Learn more about newsletter API.


An email can have one or more attachments in the form of images and/or documents. Attachments to newsletters should generally not be used, because they will have a negative impact on delivery rates, increase the loading time, and the open-rates for attachments are not measurable. Consider linking to attachments on your website instead.


Automated emails only need to be created once, and are automatically sent thereafter based on conditions that you manage. These conditions can take the form of purchase history, demographic information, registration or de-registration, or any other action (so-called trigger emails). Automated newsletters can also be sent to customers on their birthday, or after long periods of inactivity.


An autoresponder is automated email is sent as a result of a specific event. A classic example is the out-of-office email.



BCC stands for Blind Carbon Copy. You can add more email addresses in this line. All of these addresses will receive your newsletter, but are not viewable to other recipients.


The newsletter blacklist contains all of your contacts that have unsubscribed from the newsletter. These are documented, but no longer contacted.


If a newsletter sender distributes too much spam, it will become blacklisted. All the future emails from this sender will be filtered and not delivered. Blacklisting can be based on IP addresses, or based on domains. The opposite is called whitelisting, in which certain senders are classified as trusted.


Bounces are emails that were not delivered. A fail message is sent back to the sender. The reasons for bounces can include incorrect email addresses, or the server is not currentlz available.

Bounce Rate

The bounce rate is the proportion of failed deliveries to overall deliveries. It includes emails that are both temporarily and permanently failed. A persistently high bounce rate increases the likelihood that a sender will be classified as a spammer.


Call to Action

A call to action is an encouragement to take an action. Normally this is made with a button within the newsletter that your contacts are encouraged to click. Classic calls to action include “Buy Now!” or “Click now!” They should be as specific as possible.


CAPTCHA (=Completely Automated Public Turing test to tell Computers and Humans Apart) is a security mechanism to ensure that registrations are made by humans and not bots.


CC stands for carbon copy. You can add email recipients to the CC field and they will receive your email. Their email addresses and name will also be visible to all other email recipients.

Certified Senders Alliance

The Certified Senders Alliance constitutes the central German whitelist since 2005. The CSA whitelist is a positive list for email bulk senders. With ISPs and email-providers participating in the whitelist, solicited email does not need to enter the ISPs’ spamfilter any longer – the chances of false positives (legitimate email erroneously tagged as spam) are reduced. Learn more about CSA whitelisting.


A click is when a contact clicks on a link in your newsletter. It is important to differentiate between unique clicks and overall clicks.

Click Rate

The clickrate indicates what percentage of your contacts clicked on a link within your newsletter. The click rate is one of the most important statistics when evaluating your newsletter. A high click rate indicates a high level of engagement, a low click rate indicates that there’s room for improvement.


A clickmap shows exactly where in your newsletter your customers clicked. It shows which links and photos were most successful, and which content was particularly interesting for your newsletter recipients.


Email clients are programs that receive and send emails. Think Gmail, Hotmail, GMX, Yahoo, and Microsoft Outlook.


Email reports can be broken down by clustering different kinds of target groups. The contacts can be split based on all existing characteristics such as age, sex, and location. Use it to evaluate whether certain content was paritucularly interesting for different target groups.


A Content Management System (CMS) is a computer application that supports the creation and modification of digital content using a common user interface and thus usually supporting multiple users working in a collaborative environment. In our context, CMS usually refers to website content systems like WordPress.

Complaint Rate

The complaint rate tells you how many recipients marked your newsletter as spam.

Confirmed Opt-In

Using a confirmed opt-in (COI) (also known as a double opt-in) procedure helps to ensure that a third party is not able to subscribe someone else accidentally, or out of malice. For that, you need a double opt-in registration form. If no action is taken on the part of the email recipient, they will simply no longer receive any messages from the list operator.


Conversions measure an action that you would like your customers to take. For example, registering for your website or buying a product. Measuring conversions helps you determine the success of your email campaign.

Conversion Rate

Conversion rate is the proportion of conversions to the total number of newsletters.

Cookie Tracking

Tracking cookies are used to track users’ web browsing habits. This can also be done to some extent by using the IP address of the computer requesting the page or the referer field of the HTTP request header, but cookies allow for greater precision.

Character Coding

A character encoding ensures that all characters are displayed correctly in an email. If no universal font encoding is used, it may result in problems with displaying certain characters correctly. The most widespread character code is Unicode.

Commercial Emails

In order to send commercial emails to private individuals, the explicit agreement from the recipient is required. This can easily and comfortably be gained by using the double opt-in method, in which a potential subscriber to your newsletter receives an email with a confirmation link.


Customer relationship management (CRM) is an approach to managing a company’s interaction with current and future customers. The CRM approach tries to analyze data about customers’ history with a company, in order to better improve business relationships with customers, specifically focusing on retaining customers, in order to drive sales growth.


See Certified Senders Alliance.


Cascading Style Sheets (CSS) contain formating from HTML or XML sites. The content of a website and its formatting are thus kept separate.


CTR stands for click-through rate and indicates the ratior of opens : clicks. Learn here how to increase your click-through rate.

Cumulative Clicks

Cumulative clickrates indicate the total number of clicks in a newsletter. Every click is measured, including from contacts who clicked in more than one spot in your newsletter.

Cumulative Open Rate

Cumulative open rate, in contrast to the unique open rate, measures all opens. It measures all opens of your newsletter, including when a single contact opens the same newsletter twice.
In contrast to the unique open rate, all opens are taken into account, which includes multiple email opens

Customer Lifetime Provision

Under customer lifetime provision one understands an enduring revenue sharing, in comparison to a one-time finder’s fee.


Data Protection Act 1998

The Data Protection Act 1998 (DPA) is an Act of Parliament of the United Kingdom of Great Britain and Northern Ireland that defines UK law on the processing of data on identifiable living individuals. It is the main piece of legislation that governs the protection of personal data in the UK.

Dedicated IP

A dedicated IP is reserved for the use of a single email marketer. Normally, IP server traffic is shared amongst everal users. Using a dedicated server means that the marketer alone is responsible for the IP’s reputation, which directly influences delivery rates.


DomainKeys Identified Mail (DKIM) is an email authentication process that is built to identify email spamming by providing a tool to allow receiving email clients to check that incoming email from a domain is proper and authorized by that domain’s administrators. Learn how to improve your delivery rates with DKIM.

Difference between unique opens & and total opens

Unique opens only count each individual contact once. Total opens means that individual opens can be counted more than once. If a contact opens an email twice, that counts as two total opens.


Domain-based Message Authentication, Reporting & Conformance is an email authentication process. It uses the popular SPF and DKIM protocols, and includes a reporting feature that allows receivers and senders to improve and monitor the integrity of the domain from spam.


Deliverability describes the ability of an email marketing or newsletter software to successfully deliver emails to contacts. It is positively influenced through whitelisting and sender authentification methods.

Delivery Rate

The delivery rate is the percentage of emails that you sent, that were delivered successfully to your contacts’ inboxes. A consistently high delivery rate builds the reputation of an IP address. Learn how to improve your newsletter delivery rate.


The Domain Name System is a naming system for computers, servers, services or any other tool connected to the internet or a private network. Mail servers often check the DNS entry of the email sender in order to filter out spam.


The double opt in registration method is a multi-step registration process. Recipients sign up for your newsletter via a double opt-in form, and then receive an email confirmation. This email contains a link that the recipient must click on. Once they’ve clicked, they are added to your newsletter contact list and can start receiving newsletters. The two-step process serves as explicit confirmation that the contact wants to receive your newsletter.

Average Opens

Average opens indicates how often a certain recipient opens your newsletters. It is the ratio of total opens to total emails received.


Email Campaign

An email campaign is a time-defined email marketing action with a defined goal. In the email marketing field, this is an action that consists of marketing material sent to certain contacts, and which is limited to a certain period of time or a certain number of emails that are sent.

Email Marketing

Email marketing includes all measures related to sending marketing campaigns via email. The most common form is newsletters sending. Email marketing has the advantage of being inexpensive, easy to scale, and is delivered directly to your customers’ inboxes.

Email Marketing Software

Email marketing software allows the creation, design, and dispatch of email marketing campaigns. Professional email marketing software provides powerful design and dispatch features, and gives useful data-driven insights into how your contacts interact with your newsletter.

Email Program

Email programs are used to send, receive, open, edit and review emails. See Clients.

Email Service Provider

Email Service Providers are in possession of an email sever and has customers from the email branch. They make email sending architecture available for the general public.

Embedded Images

Images that are embedded within an email are displayed immediately to your contacts, even if they need to download the rest of the email.


An Emoji is a picture that indicates longer definitions or emotions or feelings. Thanks to Emojis in Unicode, you can also put them into your newsletter campaigns. They can be placed in the subject line or within the email body.

Explicit Consent

Email marketing is a form of direct marketing, and is therefore only permitted with the express consent of your contacts. Marketing without express consent risks fines and other legal consequences. The double opt-in system serves to ensure that you receive the express consent of your contacts.



A follow-up email is a followup message, for example a summary of the most important points in a meeting. There are time-sorted followups as well as activity or achievement-based followup emails.


Hard Bounce

A bounce is an automatic failure message that you will receive when a newsletter is not successfully delivered. A hard bounce is when the newsletter could not be delivered due to a permanent failure, for example the incorrect email address.


The email header is the top portion of your newsletter and contains information like email address, the content, the format and the recipients. It includes the subject, the preheader, the sender, the recipients, and the date.


Image Hosting

Images that are sent in your newsletters must be available online. Free image hosting needs to be a feature of whichever email marketing software that you use.

Image Personalization

Image personalization is an option that allows you to show certain images to certain target groups. This allows you to show men a different image than woman, for example.

Image Suppression

Certain email clients withhold your images from emails. The images are only downloaded if they’re clicked. This means that alt texts must always be included, and must be relevant both for the image and for the email.

IP Address

The IP (Internet Protocol) address is the signature of a computer. Machines that are connected to a certain network in the internet receive a unique identifying number, which is called the IP. This makes it possible to identify individual machines and computers.

IP Warmup

IP Warmup is when an IP address that is used to send emails is in the buildup phase of its reputation building. New IP addresses, without any sending history, have a higher risk of being caught by spam filters. We keep all IP addresses warm to ensure the highest possible delivery rates.


The ISIPP SuretyMail whitelisting program enables the direct delivery of emails to many internet service providers, like Hotmail, AOL, Yahoo and GoDaddy. This includes inboxes that use such spam filters as SpamAssassin or SpamCop.


Key Performance Indicator

Key Performance Indicators measure the success of email marketing campaigns. The most important KPIs are delivery rate, open rate, click rate, and conversion rate.


Landing Page

Landing pages are marketing websites. They’re sites where people land after clicking on a link that’s part of a marketing campaign. As hosts of marketing material, they are normally designed with a specific target group in mind. If a user clicks on an offer advertisement, he or she will be directed to a landing page that lists more details about that specific deal.


mailto Link

With the help of a mailto link, you can enable users to compose an email simply by clicking on the email address. The email address doesn’t need to be copied and pasted into an email client; it is created with one click.


Marketing is a central function of a company’s activities. It is intended to raise awareness of a company’s product, and encourage consumers to purchase and/or use the company’s product(s).



Newsletters are an electronic form of communication. Newsletters are sent in regular intervals and are generally created and sent by companies, associations, agencies or associations. Members, colleagues, acquaintances and customers are informed regarding offers, information, and new developments.

Newsletter Archive

Newsletter archives can be used to publish previously sent newsletters, and can be viewable by both newsletter subscribers and the general public. The archive is dynamically controlled, and automatically updated.

Newsletter Integrations

Newsletter integrations are plug-ins between email marketing software and other systems. The manual effort creating and sending newsletters can thus be reduced. Contact management is also more efficient thanks to the use of newsletter integrations. There are newsletter software integrations for E-commerce systems like Magento, plentymarkets and Shopware, CRM systems like sugarCRM or Salesforce, and CMS like WordPress or Typo3.

Newsletter Registration Form

Newsletter registration forms are used to acquire new contacts for newsletters. They are created via HTML code or Plugin, and then placed directly into websites. Contacts are only allowed to be sent explicit sales offers after direct approval. This process is managed via the Double Opt In confirmation system.

Newsletter Tracking

Newsletter tracking refers to the measurement and rating of newsletters’ performance. It measures statistics including open rates, click rates, and conversion rate. Newsletter tracking enables the sender of a newsletter to see exactly where in the newsletters his or her contacts have clicked, as well as to compare the statistics of different target groups against one another.



When a contact opens a newsletter, it is referred to as an open. Opens are a key performance indicator.

Open Rate

Open rate is the ratio of unique opens to the total number of newsletters that were sent. The larger the number of opens, the higher the open rate.


Personal Data

The information relating to an identified or identifiable person is called personal data. The term comes from the privacy policy. Email addresses are also personal data. Their use and processing is permitted only if the person concerned has given a data protection consent. Each time you pass personal information to a service provider, the inclusion of an ADV is recommended.


Personalization means that newsletters, or certain content within the newsletter, is changed depending on the contact. This can include the subject, the greeting, the photos and/or the links within a newsletter. With the help of placeholders, certain information can be inserted into a newsletter that is automatically updated to reflect the information of a given contact.

Personalized Gift Code

Personalized gift codes are generated individually for every contact that receives a newsletter. They can only be used a single time. Personalized gift codes are often used in connection with birthdays or other very personal events.


Phishing describes the attempt to acquire personal data from indivudals using fake email accounts and fake personas. This can be prevented by a closer check of the sender’s DKIM and SPF authentication identity. Many Phishing attempts land in junk folders, but some make it through to inboxes. Phishing is an illegitimate use of newsletter software.


The preheader is displayed in certain Email clients as part of the short message description. This includes Gmail. It is best to simply include a short description of the content of the newsletter.


Reactivation Campaign

A reactivation campaign is intended to convert users with a long period of inactivity to become active once again. A contact is defined as inactive when they have not opened any newsletters for a certain period of time. Typical reactivation campaign content includes special offers, rebates, gift cards, or topics that were interesting to the contact at one point in the past. Learn how to re-engage inactive subscribers.

Read Rate

The ratio of readers who opened and read a newsletter for a certain period of time.


Email recepients receive your newsletters. Also referred to as contacts. Learn here about recipient management.

Recipient management/ Address Book

In a recipient list all addresses are stored, which are available to you. Based on receiver characteristics, the contacts can be segmented. Address books can be managed separately. Learn more about recipient management.

Recommendation Engine

Using a recommendation engine, custom product recommendations are made within emails. Per software module the click paths of the receivers are tracked in the online shop, saved shopping carts and personalized recommendations are then calculated. Recommendations may be similar, popular or recently viewed products. These can be inserted per block in real time in the newsletter.


The reputation of a sender indicates how trustworthy the sender is. This is calculated using several different factors, including bounce rate, spam designations, and the quality of the message. A good reputation has positive effects on the overall delivery rate.

Responsive Design

The goal of responsive design is to have a best-possible and simultaneously user friendly display and usability for a newsletter on all devices. Most often, responsive design is used in the context of mobile devices. Emails will be displayed correctly on all devices, whether it be mobile, tablet, desktop or otherwise.


The sending infrastructure from an email marketing software can be integrated easily into another system using a programming language-independent REST API.


Simply put, retargeting converts potential clients into buyers. You can track users by placing retargeting “cookies” in their browser, which will keep track of people who visit your site and display your retargeting adverts to them once they visit other websites

Return Path

Return Path manages the world’s largest inbox whitelist, which covers more than 2.4 billion email inboxes. Senders who use ReturnPath’s whitelist have access to more than 100 international email providers, including Hotmail, Yahoo, and Comcast. Spamfilters like Cloudmark and SpamAsassin view the sender as automatically trustworthy.



Segmentation stands for the sorting of a contact list according to certain criteria. Contacts can, for example, be sorted according to demographic, geographic or activity-based traits into distinct groups. These groups can then be addressed individually and form more cohesive target groups.

Sender Address

The sender address is part of the email heading. It is displayed in the overview section and influences the delivery and open rates of your newsletter campaign. Using an email marketing software, you can choose whichever sender address you would like.

Sender Score

The sender score is a free service by Return Path and shows the email reputation of a sender. An algorithm rates the reputation of the IP address on a scale from 1-100. The lower the score, the more difficult the delivery. The rating includes the unsubscribe rates and bounce rates.

Series Mailing

See Automation.

Shared IP

A shared IP is an IP address that is used by several senders. This means that the responsibility for the reputation of the IP address is also shared.

Soft Bounce

Soft bounces occur when emails are unable to be delivered due to temporary errors. This can for example happen when the inbox of a contact is too full. Addresses that are rejected due to soft bounces can be delivered to an inbox at a later time.


Spam, or junk, is email that contains advertising material that is mostly unwanted and annoying. In order to remain free from spam suspicions, email marketing procedures should be legally compliant. This means that contacts need to give explicit approval through the double opt in process.

Spam Trap

Spam traps were developed in order to identify senders of spam. They can be identified by using double opt in registration methods. Senders who land in a spam trap are blacklisted, meaning their reputation suffers.


SPF (Sender Policy Framework) is a simple and widely used method to authenticate emails. The sender of an email makes it known, which servers have the authority to use his or her name.

Standard Mailing

A standard mailing is sent a single time from the sender at a certain time period. Classic newsletters are most often standard mailings.


The subject is the headline, or title, of your newsletter. The subject is, along with the sender address, the most important information that determines whether your email is opened. It’s very important for the overall success of your email campaign.

Subject Line

The subject line is the field in which you write your subject. It should be short, precise, and clearly formulated. Different variants can be tested using A/B tests. Learn how to craft great subject lines.



An email template is a a design template for newsletters and other kinds of emails. It speeds up the creation of emails, because layouts and formatting is already taken care of, and all that needs to be done is importing content. Templates can be created manually or can be ordered from professional designers. Here you can learn more about template creation and here you see newsletter template examples.

Text Version

There is a distinction between HTML and text versions. Every email client has specific settings that determine whether a contact can see an email in HTML and text format. Some recipients have their email clients set so that they can see only plain text. It is therefore important that each email contains a text version. In order for the email not to be categorized as spam, the text version must match the version of HTML as much as possible.

Time Controlled

Professional newsletter software offers the functionality of time controlled newsletters. This means that you can schedule newsletters to be sent at some point in the future – tommorrow, next week, or even next year.


Tracking generally refers to the collection and analysis of user behavior on websites. In email marketing, the behavior of the recipient can be tracked with the aim to better tailor newsletters to the recipient. Among the metrics that can be tracked include the open rate, click through rate and conversion rate. Openings and clicks can also be localized.

Tracking Domain

A tracking domain is used to track newsletters. In order for clicks within the newsletter to be measured, this is invisibly sent via a neutral website, where the clicks are then recorded. Newsletter2Go uses a premium tracking domain, but you can also use your own Domain.

Tracking Link

A tracking link makes it possible to understand the actions of contacts. It includes defined parameters that enable an exact classification of contacts and actions. With a click on a tracking link, the contact is directed to a domain of your choice.

Tracking Pixel

A tracking pixel is a transparent micro graphics, which makes it possible to detect the openings of a newsletter. Once this is displayed, it can be determined who has accessed the image when and from where. This means that the opening rate can only be reliably determined when images are loaded.


Traits in email marketing are descriptors of contacts. Traits can include gender, birth date, purchase history, or place of residence. Using email marketing and newsletter software, contacts can be sorted and arranged based on shared traits. This allows target groups to be built and addressed with specifically targeted newsletters.

Transaction email

Transaction emails are newsletters that are sent in reaction to defined actions by contacts. This can include payments made by customers or users, booking confirmations, entrance confirmations and registration confirmations. They are triggered by a certain action.

Trigger Mailing

A trigger mailing is an automated email that is dispatched when a user or customer has taken a certain action. For example, when an item is placed in a shopping cart or when a link is clicked.



Unicode is a standard created by the computing industry for the consistent encoding, representation, and handling of text expressed in most of the world’s writing systems.

Unique Clicks

The unique clicks are the total number of clicks in your newsletter. This indicates the total number of recipients who’ve clicked a link in your email.

Unique Clickrate

The unique clickrate indicates what proportion of your contacts clicked on at least one link in your newsletter. Every contact is only counted once, multiple clicks are not counted.


All newsletters need to have a visible and functioning button that allows contacts to unsubscribe. This is a legal and regulatory requirement.

URL Coding

URL Coding oder URL Encoding describes a mechanism in which to code certain information in a URL. This is necessary, for example, if a certain symbol in a URL is not displayable.


Webshop / E-Commerce

A Webshop or E-commerce merchant advertises and sells goods and services online. Webshops and E-commerce platforms can have real-world stores, or be exclusively online.


A webversion ensures that a newsletter can be viewed independently from the email client. This ensures that the newsletter can, in doubt, always be displayed properly. A link to the website should always be included in the newsletter itself.

Welcome email

A welcome email is automatically send as soon as a contact has registered with an online shop or subscribed to a newsletter. The sender uses this welcome mail to build trust with their customer from the very beginning of their relationship.


White-labeling means that the software is viewed and accessed using the colors, brand and design of a third-party. This is particularly relevant for digital marketing agencies who would like to use the platform as a service solution for their clients, but who would like the clients to see only the agency’s design.


The whitelist is the counterpart to the blacklist. It is a “positive list” that includes the e-mail addresses or IPs of people or companies that are regarded as trustworthy. Senders who are listed in a whitelist, can send emails directly into the mailbox of their contacts. The delivery rates rise significantly because there is no risk of being wrongly intercepted by spam filters. Learn here about newsletter whitelisting.

Worldwide Sending

Worldwide sending capabilities is a large advantage for email marketing. Email addresses from around the world can be reached just as easily as addresses from around the corner. Time-sensitive mails can be sent at varying times throughout the day.



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