Email Marketing Glossary

76 essential terms every newsletter creator should know — from deliverability and analytics to AI-powered publishing.

Deliverability & Infrastructure

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.

Metrics & Analytics

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.

Strategy & Tactics

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.

Subscriber Management

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.

Newsletter-Specific

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.

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