Email Marketing Glossary

Email Deliverability

Email deliverability is the ability of an email to successfully reach the recipient's inbox rather than being filtered to spam or bounced.

Bounce Rate

Bounce rate is the percentage of sent emails that could not be delivered to the recipient's mailbox.

Hard Bounce

A hard bounce is a permanent email delivery failure where the recipient address is invalid, doesn't exist, or the receiving server has permanently rejected the message.

Soft Bounce

A soft bounce is a temporary email delivery failure caused by issues like a full inbox, server downtime, or a message that exceeds size limits.

SPF Record

An SPF (Sender Policy Framework) record is a DNS TXT record that specifies which mail servers are authorised to send email on behalf of your domain.

DKIM

DKIM (DomainKeys Identified Mail) is an email authentication method that uses cryptographic signatures to verify that an email was sent by the domain it claims to be from and hasn't been tampered with in transit.

DMARC

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol that builds on SPF and DKIM to prevent email spoofing and provide reporting on authentication results.

Email Authentication

Email authentication is a set of protocols (SPF, DKIM, DMARC) that verify the sender's identity and ensure emails haven't been forged or tampered with.

IP Warming

IP warming is the process of gradually increasing the volume of emails sent from a new IP address to build a positive sender reputation with email providers.

Email Reputation

Email reputation (or sender reputation) is a score assigned to your sending domain and IP address by email providers, reflecting how trustworthy your emails are.

Spam Score

Spam score is a numeric rating assigned to an email by spam filters that predicts how likely the message is to be classified as spam.

Spam Trap

A spam trap is an email address used by ISPs and anti-spam organisations to identify senders with poor list practices.

Email Blacklist

An email blacklist (or blocklist) is a real-time database of IP addresses and domains identified as sources of spam.

Sender Score

Sender Score is a numeric reputation rating (0-100) for an outgoing mail server IP address, calculated by Validity (formerly Return Path).

Return Path

The Return-Path (also called envelope sender or bounce address) is the email address where bounce notifications and delivery status reports are sent.

MX Record

An MX (Mail Exchanger) record is a DNS record that specifies the mail server responsible for receiving emails on behalf of a domain.

Email Sender Reputation

Email sender reputation is a score, or set of scores, that internet service providers and mailbox providers assign to your sending identity based on your historical sending behaviour, which determines whether your emails land in the inbox, the spam folder, or get blocked entirely.

Email Authentication (SPF, DKIM & DMARC)

Email authentication is the set of technical protocols, specifically SPF, DKIM, and DMARC, that prove to receiving mail servers that your emails are genuinely sent from you and not forged by a third party.

Open Rate

Open rate is the percentage of delivered emails that were opened by recipients, calculated as (unique opens ÷ delivered emails) × 100.

Click-Through Rate (CTR)

Click-through rate is the percentage of delivered emails where at least one link was clicked, calculated as (unique clicks ÷ delivered emails) × 100.

Click-to-Open Rate (CTOR)

Click-to-open rate is the percentage of opened emails that received at least one click, calculated as (unique clicks ÷ unique opens) × 100.

Conversion Rate

Conversion rate is the percentage of email recipients who completed a desired action after clicking through from the email.

Unsubscribe Rate

Unsubscribe rate is the percentage of email recipients who opted out of receiving future emails, calculated as (unsubscribes ÷ delivered emails) × 100.

List Growth Rate

List growth rate is the speed at which your email subscriber list is growing, accounting for new subscribers, unsubscribes, and bounces.

Email ROI

Email ROI (Return on Investment) is the revenue generated from email marketing divided by the cost of running email campaigns, expressed as a ratio or percentage.

Revenue Per Email

Revenue per email (RPE) is the average amount of revenue generated from each email sent, calculated as total revenue attributed to email divided by the number of emails sent.

Engagement Score

An engagement score is a composite metric that combines multiple signals (opens, clicks, replies, forwards) to measure how actively a subscriber interacts with your emails.

Read Rate

Read rate estimates the percentage of subscribers who actually read your email content, as opposed to simply opening it briefly.

Email Open Rate

Email open rate is the percentage of delivered emails that recipients open, calculated by dividing unique opens by the number of successfully delivered emails and multiplying by 100.

Newsletter Subscriber Churn Rate

Newsletter subscriber churn rate is the percentage of subscribers who leave your list over a given period, either by unsubscribing, marking your emails as spam, or becoming completely inactive.

Newsletter Open Rate Benchmark

A newsletter open rate benchmark is an industry reference point that tells you what percentage of subscribers typically open emails in a given niche or sector, used to judge whether your own open rates are strong, average, or cause for concern.

Email Click-Through Rate

Email click-through rate (CTR) is the percentage of recipients who clicked at least one link in your email, calculated by dividing total clicks (or unique clicks) by the number of emails delivered.

Newsletter Engagement Rate

Newsletter engagement rate is a composite metric that measures how actively subscribers interact with your newsletter, typically combining opens, clicks, replies, and other signals into a single score that reflects audience health.

Newsletter Open Rate Benchmarks

Newsletter open rate benchmarks are industry-standard reference points that help creators judge whether their email open rates are performing below, at, or above average for their niche or list size.

Email Bounce Rate

Email bounce rate is the percentage of sent emails that failed to reach the recipient's inbox, calculated by dividing total bounces by total emails sent and multiplying by 100.

Email Bounce Rate (Newsletter)

Email bounce rate for newsletters is the percentage of sent emails that failed to reach subscribers' inboxes, either temporarily or permanently, expressed as a proportion of total emails sent.

A/B Testing

A/B testing (or split testing) is the practice of sending two or more variations of an email to different portions of your audience to determine which performs better.

Subject Line

The subject line is the text displayed in a recipient's inbox that summarises the email content and determines whether they open it.

Preheader Text

Preheader text is the short summary text that appears next to or below the subject line in an email inbox preview.

Call to Action (CTA)

A call to action is a prompt in your email that tells the reader what action to take next, typically displayed as a button or linked text.

Personalisation

Email personalisation is the practice of tailoring email content, subject lines, or offers to individual subscribers based on their data, preferences, or behaviour.

Segmentation

Email segmentation is the practice of dividing your subscriber list into smaller groups based on shared characteristics, behaviours, or preferences.

Dynamic Content

Dynamic content is email content that changes automatically based on the recipient's data, preferences, or behaviour, showing different content blocks to different subscribers within the same email.

Email Automation

Email automation is the use of triggers, rules, and scheduled workflows to send emails automatically based on subscriber actions or time-based conditions.

Drip Campaign

A drip campaign is a series of pre-written, automated emails sent on a timed schedule to guide subscribers through a specific journey or educational sequence.

Welcome Series

A welcome series is an automated sequence of emails sent to new subscribers immediately after they join your list, designed to introduce them to your newsletter and set expectations.

Re-engagement Campaign

A re-engagement campaign (or win-back campaign) is a targeted series of emails sent to inactive subscribers to encourage them to start engaging with your content again.

Win-back Email

A win-back email is a targeted message sent to inactive or churned subscribers to encourage them to re-engage with your newsletter.

Triggered Email

A triggered email is an automated message sent in response to a specific subscriber action or event, such as signing up, clicking a link, or reaching a milestone.

Transactional Email

A transactional email is an automated message triggered by a user's action on your platform, such as a password reset, subscription confirmation, or receipt.

Email List Segmentation

Email list segmentation is the practice of dividing your subscriber base into smaller, distinct groups based on shared characteristics, so you can send more relevant content to each group.

A/B Testing Email Subject Lines

A/B testing email subject lines is the practice of sending two or more subject line variants to separate portions of your list to determine which drives higher open rates before sending the winner to the remainder.

Double Opt-In

Double opt-in is a two-step subscription process where a new subscriber must confirm their email address by clicking a verification link before being added to your list.

Single Opt-In

Single opt-in is a subscription process where a subscriber is added to the email list immediately after entering their address, without a confirmation step.

Email List

An email list is a collection of email addresses belonging to people who have given permission to receive emails from you.

List Hygiene

List hygiene is the practice of regularly cleaning your email list by removing invalid, inactive, or unengaged subscribers to maintain list quality and deliverability.

Subscriber Lifecycle

The subscriber lifecycle is the progression of stages a subscriber goes through from initial signup to long-term engaged reader or eventual churn.

Lead Magnet

A lead magnet is a free piece of valuable content offered in exchange for a visitor's email address to grow your subscriber list.

Opt-In Form

An opt-in form is a web form where visitors enter their email address to subscribe to your newsletter or email list.

Landing Page

A landing page is a standalone web page designed with a single goal: converting visitors into email subscribers.

Subscriber Churn

Subscriber churn is the rate at which subscribers leave your email list through unsubscribes, bounces, or spam complaints.

Email Preference Centre

An email preference centre is a page where subscribers can manage their email preferences, choosing which types of content they receive and how often.

Double Opt-In Email

A double opt-in email is the confirmation message sent to a new subscriber asking them to verify their email address before they're added to your list.

Email List Cleaning

Email list cleaning is the process of removing invalid, inactive, or unengageable addresses from your subscriber list to protect deliverability and maintain accurate performance data.

Newsletter

A newsletter is a regularly distributed email publication that delivers curated content, updates, or insights to a list of opted-in subscribers.

Newsletter Platform

A newsletter platform is a software service that provides the tools to create, send, manage, and grow email newsletters.

Email Newsletter

An email newsletter is a regularly scheduled email sent to subscribers containing curated news, insights, updates, or educational content on a specific topic.

Newsletter Monetisation

Newsletter monetisation refers to the various strategies used to generate revenue from an email newsletter.

Paid Newsletter

A paid newsletter is an email publication that charges subscribers a recurring fee (usually monthly or annual) for access to premium content.

Newsletter Growth

Newsletter growth encompasses the strategies and tactics used to increase a newsletter's subscriber base over time.

Newsletter Sponsorship

A newsletter sponsorship is a paid advertisement placed within a newsletter, where a brand pays the newsletter creator to promote their product or service to the subscriber base.

Cross-Promotion

Cross-promotion is a growth strategy where two or more newsletter creators recommend each other's newsletters to their respective audiences.

Content Curation

Content curation is the process of selecting, organising, and presenting the most relevant and valuable content from multiple sources for your newsletter audience.

Editorial Calendar

An editorial calendar is a planning tool that maps out newsletter content topics, themes, and publication dates in advance.

Newsletter Subject Line

The short line of text that appears in a subscriber's inbox before they open an email, acting as the primary trigger for whether they open your newsletter or ignore it.

Newsletter Landing Page

A dedicated web page designed specifically to convert visitors into newsletter subscribers, typically featuring a description of the newsletter's value, social proof, and a prominent sign-up form.

Newsletter Growth Rate

Newsletter growth rate is the percentage by which your subscriber list increases over a given period, calculated by measuring net new subscribers (gains minus losses) against your starting subscriber count.

Welcome Email Newsletter

A welcome email newsletter is the first message sent to a new subscriber immediately after they join your list, serving as both a formal introduction to your publication and the foundation of the reader relationship.

CAN-SPAM Act

The CAN-SPAM Act is a US law (2003) that sets rules for commercial email, including requirements for opt-out mechanisms, honest subject lines, and sender identification.

GDPR

The GDPR (General Data Protection Regulation) is a European Union law that governs how personal data (including email addresses) is collected, processed, and stored.

CASL

CASL (Canada's Anti-Spam Legislation) is Canadian law that regulates commercial electronic messages, requiring express consent before sending marketing emails to Canadian recipients.

Unsubscribe Link

An unsubscribe link is a clickable link included in marketing emails that allows recipients to opt out of receiving future messages.

List-Unsubscribe Header

The List-Unsubscribe header is an email header that provides email clients with a machine-readable way to offer one-click unsubscription directly from the inbox interface.

Email Consent

Email consent is the permission given by an individual to receive marketing or newsletter emails, obtained through explicit opt-in or documented agreement.

Privacy Policy

A privacy policy is a legal document that explains how an organisation collects, uses, stores, and protects personal data, including email addresses and subscriber information.

AI Newsletter

An AI newsletter is a newsletter created with the assistance of artificial intelligence, using AI tools for content research, writing, image generation, or distribution optimisation.

AI Email Writing

AI email writing is the use of artificial intelligence models to generate, draft, or refine email content including newsletter articles, subject lines, and calls to action.

Generative AI for Email

Generative AI for email refers to the application of generative artificial intelligence models to create email content, images, designs, and strategies from scratch.

Newsletter Automation

Newsletter automation is the use of technology to automate repetitive tasks in the newsletter creation and distribution process, from content generation to send scheduling.

Smart Send Time

Smart send time (or send time optimisation) is the use of data and algorithms to determine the optimal time to send emails to each subscriber for maximum engagement.

Predictive Analytics

Predictive analytics uses historical data, statistical algorithms, and machine learning to forecast future subscriber behaviour, such as churn risk, engagement trends, and optimal content strategies.