The world of SEO (Search Engine Optimisation) is filled with jargon and acronyms that can be be confusing to the occasional visitor. To help you understand what’s what in plain English, we’ve put together this comprehensive overview of SEO terms and concepts, cross-referenced where appropriate to show how they interrelate.
A
Algorithm
A set of rules used by search engines like Google to decide how pages are ranked. These algorithms weigh hundreds of factors — from page speed to backlinks — to determine where your website appears in search results.
Alt Text
Alternative text (or “alt text”) is a written description of an image that helps visually impaired users understand the content and provides context for search engines. Including clear, keyword-relevant alt text enhances website accessibility and supports image-based SEO efforts.
Anchor Text
The visible, clickable words in a hyperlink. Ideally, it should describe the destination page and include keywords where appropriate.
B
Backlink
When another website links to yours. These links act like endorsements and are one of the most powerful ranking signals in SEO.
Bounce Rate
The proportion of visitors who arrive on your site and exit without interacting with any other elements. A high bounce rate may indicate that your page is not fulfilling the expectations of visitors.
Black Hat SEO
Shady tactics that try to game the system — like hidden text or buying links. They may give short-term results, but search engines will eventually penalise you.
C
Canonical Tag
A small piece of code that informs search engines which version of a page is the ‘primary’ one. It helps to avoid problems with duplicate content.
Conversion Rate
Conversion rate is the percentage of individuals who visit your website and go on to achieve a particular objective — such as filling out an enquiry form, subscribing to a newsletter, or completing a purchase. It is among the most significant indicators in digital marketing, as it clearly demonstrates how well your website transforms visitors into measurable outcomes. An increased conversion rate typically indicates a positive user experience, appropriate traffic, and effective calls to action.
Crawling
The process by which search engine bots explore your website to understand and index its content.
CTR (Click-Through Rate)
The ratio of people who see your link in the search results and actually click on it.
D
Domain Authority (DA)
The Domain Authority is a metric that was originally created by Moz which estimates how likely a website will perform in search engine rankings.
Duplicate Content
Duplicate content is where content on a website is identical—or nearly identical—across multiple web pages. When search engines detect duplicate content, it can lead to confusion about which version to prioritise, potentially reducing visibility in search results.
E
E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness)
A principle Google uses to assess the quality of content, especially in sensitive areas like health or finance.
External Link
A link pointing to a different website. Adding links to relevant, high-quality sources helps your SEO and your readers.
F
Featured Snippet
A highlighted result at the top of Google’s results page, often in a box. Getting a featured snippet can massively boost visibility.
Follow Link
Follow link is a hyperlink that passes authority from one site to another site. These links influence SEO rankings.
G
Google Analytics
A free tool that tracks who visits your site, what they do, and how they got there. Essential for measuring SEO performance.
Google Search Console
A free dashboard provided by Google where you can see how your site performs in search, fix issues, and submit sitemaps.
H
Header Tags (H1, H2, etc.)
HTML header tags are the headings in a web page that organise your content. The H1 is your primary heading, followed by secondary headings (H2, H3, etc.). Search engines use these to interpret your content.
HTML (HyperText Markup Language)
The standard language used to build web pages. Clean, well-structured HTML helps your site load faster and get indexed properly.
I
Index
The index is the central storage system used by search engines to catalogue web content they’ve discovered during crawling. If a web page isn’t included in this digital library, it won’t be eligible to appear in search engine results.
Internal Link
An internal link is a clickable component that takes the user of the site from one page on your website to a different page within the same site. These links enhance user navigation, assist in creating a smoother user journey, and aid search engines in comprehending the connection between your pages, which helps to strengthen site structure and SEO effectiveness.
K
Keyword
A keyword refers to a particular word or phrase that someone enters into a search engine when seeking information.
Keyword Density
How often a keyword appears in your content, usually expressed as a percentage.
Keyword Stuffing
Unnaturally cramming a page with keywords to try and manipulate rankings. It’s outdated and penalised by search engines.
L
Landing Page
A page specifically designed to receive visitors from a particular campaign or source — often used in PPC or lead generation.
Link Building
Link building is a strategic process where you build up links from external websites that point to your website. These inbound links act like trust signals for search engines, indicating your content is trustworthy and authoritative.
Long-Tail Keyword
A longer, more specific keyword phrase (e.g. “affordable SEO consultant in Birmingham”) is typically easier to achieve a higher ranking for and tends to convert more effectively.
M
Meta Description
A brief summary of your page’s content, displayed in search results beneath the title. While it doesn’t directly influence rankings, it can help increase click-through rates.
Meta Tags
Tags in your website’s code that provide metadata about the page. These include the title tag, meta description, and others that help search engines understand your content.
Mobile-First Indexing
Google primarily evaluates and ranks websites using the mobile version of their content. This shift means that if your site isn’t fully optimised for smartphones and tablets—whether that’s due to poor responsiveness, slow load speeds, or missing content—your search visibility could take a hit. A seamless mobile experience is now essential for strong performance in the search results.
N
Nofollow Link
A nofollow link refers to a hyperlink that contains the rel="nofollow" tag within the HTML markup. This directive signals to search engines not to pass on any ranking value to the target page. In effect, it ensures the hyperlink does not influence the search engine optimisation standing of the linked website. This approach allows site administrators to exercise greater discretion over which outbound links benefit from their site’s link authority.
Noindex
A directive that tells search engines not to include a particular page in their search results.
O
Off-Page SEO
Activities done outside your own website to boost rankings — like gaining backlinks, mentions, or social signals.
On-Page SEO
The process of optimising content, tags, structure, and internal links on your website to improve rankings.
Organic Traffic
This refers to users who land on your website by clicking on non-paid listings in search engine results. Growing organic traffic is a key goal of SEO, as it reflects visibility and relevance without relying on advertising spend.
P
Page Authority (PA)
Like Domain Authority, but for a specific page rather than an entire site. Another Moz metric, helpful for competitive analysis.
Page Speed
How quickly your page loads. Affects user experience and rankings. Faster is always better.
PPC (Pay-Per-Click)
An advertising approach in which you are charged whenever someone clicks on your advert — Google Ads is the most widely used platform.
R
Redirect
A redirect is a mechanism that forwards visitors and search engines from one web address to another. This is typically required if a page has been moved or is no longer available. The most common form is a 301 redirect, which signals a permanent relocation and helps maintain existing SEO strength.
Robots.txt
A robots.txt file is a plain text document placed in the root folder of your website. It provides instructions to search engine crawlers, outlining the areas of the site they are permitted to access and index.
S
Schema Markup
Schema is a type of structured data added to your website’s code to give search engines more detail about the content on your pages — for example, identifying a review, event, product, or FAQ. It can enhance your listings with rich snippets like star ratings, images, or dates.
Search Engine
A search engine (like Google, Bing or DuckDuckGo) is an online system that discovers, organises, and ranks content to help users find information relevant to their queries.
SEO (Search Engine Optimisation)
SEO refers to the process of enhancing a website to improve how well it appears in non-paid results on search engines. This encompasses areas such as behind-the-scenes technical improvements, content within web pages, and external efforts like acquiring quality backlinks and carrying out online public relations.
SERP (Search Engine Results Page)
The SERP is the webpage that appears once a search term has been entered into a search engine. It generally displays a variety of result types — including unpaid web pages, sponsored ads, highlighted answer boxes, map-based listings, video results, image previews, and product carousels — all tailored to suit the searcher’s intent.
Sitemap
A sitemap is a structured file, usually in XML format, that lists key URLs on a site. Its purpose is to help search engines discover and index site content efficiently, reducing the chance that crucial web pages will be missed during a crawl.
T
Technical SEO
This involves optimising the infrastructure of your website so that search engines can easily crawl, interpret, and index your pages. It includes improving page speed, ensuring mobile responsiveness, enabling HTTPS, reducing crawl errors, and maintaining a clear site structure.
Title Tag
The title tag is an HTML element that specifies the title of a web page, as displayed in browser tabs and search engine results. It is a key ranking factor and should clearly convey the topic of the page while naturally including important search terms.
Traffic
Website traffic refers to the total number of visitors who land on your site. People reach your site through a variety of channels, including:
- Organic (search engines)
- Paid (PPC advertising)
- Direct (typing the URL)
- Referral (other websites)
- Social (platforms like Facebook or LinkedIn)
Tracking traffic helps evaluate your digital performance and optimise strategy.
U
URL (Uniform Resource Locator)
A URL is the web address that directs visitors to a specific location on your website. Search-friendly URLs are typically concise, descriptive, and contain relevant keywords. This makes it easier for search engines to understand the page content and enhances usability for visitors.
User Experience (UX)
UX describes how straightforward, pleasant, and effective it is for people to use your website.
Positive UX lowers the likelihood of visitors leaving quickly, encourages them to stay longer, and raises the probability of them taking action — all of which are crucial for both user satisfaction and search engine performance.
V
Voice Search
Using verbal commands to perform searches, typically through mobile devices or voice-activated assistants. Enhancing a site for voice requires an emphasis on conversational phrasing and content that addresses common questions.
W
Web Crawler
Also referred to as a “spider” or “bot”, a web crawler is a tool that search engines employ to explore online pages and gather information. It autonomously moves through websites, capturing new or updated material so that it may be added to the search engine’s index.
White Hat SEO
These are ethical SEO strategies that stick to search engine rules and focus on long-term success. White hat SEO prioritises user experience, valuable content, and legitimate backlink-building rather than trying to manipulate rankings through shortcuts.
Y
YouTube SEO
This is the practice of optimising videos so they perform better on YouTube and in Google search. Key elements include using targeted keywords in titles and descriptions, designing engaging thumbnails, boosting viewer engagement, and organising content effectively through playlists.
Hopefully this glossary has helped you demystify the complex terminology of SEO, providing clear definitions that help you better understand what your SEO agency is saying, or help you create your own SEO strategies more intelligently.
