If you’re new to SEO or just need a refresher, this glossary breaks down the key terms you’ll come across. You’ll find clear, practical explanations for common concepts like backlinks, heading tags, alt text, keyword research and more.
Whether you’re trying to boost rankings, understand what your web dev is talking about, or just make sense of a Google report—this list will help. It’s written in plain language, with examples where needed. No fluff. Just useful info you can refer to anytime. Use it to spot gaps in your knowledge or get quick answers while you work.
301 Redirect
A 301 redirect sends visitors and search engines from one URL to another permanently. It’s used when a page has moved to a new address. Search engines pass most of the original page’s SEO value to the new URL.
Alt Text
Alt text is added to image tags in HTML. If the image can’t load, the alt text shows up instead. It also helps search engines understand what the image is, which can improve SEO.
Anchor Text
Anchor text is the clickable part of a link. It should describe what the linked page is about. Search engines use it to figure out what the destination page covers.
Backlinks
Backlinks are links from other websites that point to your site. They help boost your authority and rankings, especially if the linking sites are trusted and relevant.
Black Hat
Black hat SEO uses dodgy tactics like keyword stuffing, hidden links, and spammy backlinks. These can get your site penalised or removed from search results. What’s considered black hat can change over time.
CSS (Cascading Style Sheets)
CSS is the code that controls how your website looks—fonts, colours, spacing, layout. It works alongside HTML and is a big part of front-end design.
CTR (Click-Through Rate)
CTR is the percentage of people who click on your link after seeing it. It’s calculated by dividing clicks by impressions. A strong meta title and description can help improve it.
Canonical URL
A canonical tag tells search engines which version of a page is the “main” one if there are duplicates. It helps prevent issues with duplicate content.
Core Algorithm Updates
Major changes Google makes to its ranking system that can significantly impact search results. These updates often target content quality, user experience, or specific SEO practices.
E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness)
Google’s framework for evaluating content quality. It considers the creator’s experience with the topic, their expertise, the site’s authority, and overall trustworthiness.
The Fold
The fold is where the screen cuts off before scrolling. Content above the fold loads first and gets the most attention, so use that space wisely – headlines, calls to action, key info. This varies between mobile and desktop devices.
Google Ads
Google Ads is a paid advertising platform. You bid on keywords to get your ads shown in search results. You only pay when someone clicks.
Google Analytics
Google Analytics tracks what visitors do on your site. It shows where they came from, what they viewed, how long they stayed, and more. It’s free and packed with data.
Googlebot
Googlebot is the crawler that visits your site and adds your pages to Google’s index. There’s a desktop and mobile version, depending on what kind of device it’s simulating.
Google My Business
Google My Business lets local businesses show up on Google Maps and in the local results. You can add your hours, contact details, and reviews. Google My Business in 2024 was renamed Google Business Profile.
Google Search Console
Google Search Console helps you monitor your site’s search performance. You can track indexed pages, fix errors, and see what keywords bring you traffic.
Heading Tags
Heading tags (H1 to H6) structure your content. H1 is usually your main title. Use them in order to help search engines and readers understand your page layout.
HTML (Hypertext Markup Language)
HTML is the foundation of every website. It tells browsers how to display content. SEO tweaks like meta tags, heading structure, and schema are all done in HTML.
HTTP Status Codes
Three-digit codes that indicate the status of a web page request. Common ones include 200 (success), 404 (not found), and 500 (server error). Important for technical SEO troubleshooting.
JavaScript
JavaScript is used to make websites interactive—things like sliders, pop-ups, live updates, and form validation. It can slow down your site if overused.
Keyword Research
Keyword research helps you find what people are searching for. You use that info to create content and target the right phrases to attract traffic.
Keyword Cannibalisation
This happens when multiple pages on your site target the same keyword. It confuses search engines and weakens your rankings. Fix it by merging pages or adjusting the keywords.
LSI Keywords
LSI (Latent Semantic Indexing) keywords are related terms that support your main keyword. They help search engines understand context.
Local Pack
The map results that appear in local searches, usually showing three businesses with their locations, ratings, and key details. Also called the “map pack.”
Long-Tail Keywords
Long-tail keywords are longer and more specific search phrases. They usually have lower search volume but higher intent.
Link Juice
Link juice is the value passed from one page to another through links. Pages with more authority pass on more juice.
Keyword Density
Keyword density is how often a keyword appears compared to total word count. Too little, and search engines might miss the point. Too much, and you risk keyword stuffing.
Meta Title
The meta title is the title shown in search results and browser tabs. Keep it short, relevant, and include your target keyword.
Meta Description
The meta description is the short blurb under your title in search results. It doesn’t impact rankings, but it can improve CTR.
Mobile-First Indexing
Google’s approach of primarily using the mobile version of a website for indexing and ranking. Desktop versions are now secondary considerations.
Noindex & Nofollow
“Noindex” tells search engines not to include a page in search results. “Nofollow” tells them not to pass link juice to a linked page.
On-Site Optimisation
This refers to SEO changes made directly on your website – things like headings, internal links, keyword use, and image optimisation.
Off-Site Optimisation
Off-site optimisation includes anything done away from your website to improve SEO – mostly backlinks, content promotion, and social signals.
Page Experience Signals
Google’s ranking factors focused on user experience, including page speed, mobile-friendliness, safe browsing, and Core Web Vitals.
Page Speed
Page speed is how fast your site loads. It affects user experience and rankings. A slow site can hurt your SEO and increase bounce rates.
Pillar Pages
Comprehensive pages that cover a broad topic in depth, designed to be the main hub for a topic cluster. They link to and are supported by related subtopic pages.
Robots.txt
This file tells search engine bots which parts of your site they can and can’t crawl. Useful for blocking admin pages or duplicate content.
Schema (Structured Data Markup)
Schema is extra code you can add to your site to help search engines understand your content. It can lead to rich results in search listings.
Search Engine
A search engine indexes websites and delivers relevant results when users type in a query. Google is the biggest, but others like Bing and Yahoo still have users.
Search Intent
The underlying goal or purpose behind a user’s search query. Understanding whether someone wants information, to make a purchase, or find a specific website helps create better-targeted content.
SERP (Search Engine Results Page)
The SERP is what shows up after you search. It includes paid ads, organic results, featured snippets, maps, and more.
Sitemap
A sitemap is a file that lists all your important pages. It helps search engines find and crawl your content faster.
Topic Clusters
A content strategy where you create a pillar page on a broad topic and link it to multiple related subtopic pages, creating a cluster of interconnected content.
UX (User Experience)
UX is how people feel when using your site. A good UX means it’s fast, easy to navigate and works well on all devices.
Voice Search
Search queries made using voice commands through smart speakers, phones, or other voice-enabled devices. Often involves longer, more conversational queries.
White Hat
White hat SEO follows the rules. It focuses on quality content, proper structure, and earning backlinks.
YMYL Pages (Your Money or Your Life)
Pages that could impact a person’s health, safety, finances, or well-being. Google holds these pages to higher E-E-A-T standards and scrutinises their content quality more closely.
Additional Terms
Bounce Rate
Percentage of visitors who leave after viewing one page.
Broken Link
A hyperlink that points to a page that no longer exists.
Caching
Saves a version of your website so it loads faster.
Cloaking
Shows different content to users and search engines. A black hat technique.
CMS (Content Management System)
Software like WordPress that helps manage website content.
Core Web Vitals
Google’s metrics that measure speed, interactivity, and layout stability.
Crawl
When bots visit your site to discover and index pages.
Crawl Budget
The number of pages Google will crawl on your site in a given period.
Crawl Errors
Issues that prevent search engines from successfully accessing and indexing your pages, such as 404 errors, server timeouts, or blocked resources.
De-indexing
When a page or site is removed from search engine results.
Disavow
Tells Google to ignore certain backlinks.
Domain Authority
A score from 1 to 100 that predicts a site’s ability to rank. This is a Moz-specific metric, not an official Google ranking factor.
Duplicate Content
Identical or similar content on multiple pages.
Evergreen Content
Content that stays useful over time.
Featured Snippet
A highlighted answer box shown at the top of search results. Also known as “position zero.”
Geo-targeting
Targeting content or ads based on a user’s location.
Internal Linking
Links between pages on the same site.
Indexing
Adding pages to a search engine’s database.
Keyword Stuffing
Overloading content with keywords.
Local SEO
SEO focused on showing up in local search results.
Manual Action
A penalty from Google for violating its guidelines.
NAP
Name, Address, Phone Number. Key for local SEO.
Organic Traffic
Traffic from unpaid search results.
Penalty
Ranking loss due to breaking search engine rules.
Redirect Chain
Multiple redirects between pages.
Referral Traffic
Traffic from other websites.
Sandbox
An unconfirmed idea that new sites may be temporarily held back in rankings.
Scraped Content
Content copied from other sites.
Thin Content
Pages with very little useful or original content.
Title Tag
The HTML tag for your page title.
URL Slug
The part of the URL that identifies a page.
Web Crawler
Bots used by search engines to scan and index websites.
XML Sitemap
A file listing your site’s important pages.