SEO: A to Z

Google logo

I have intentionally only included terms that have at least some modern relevance within SEO in 2021.


ALT Attributes

This is a tag which allows the webmaster to describe an image in terms a search engine can understand (that is, in text). Short but information ALT tags are a part of image optimisation best practices.


Formerly Accelerated Mobile Pages but now known officially as AMP. This is/was a project started by Google to dramatically increase the speed of page load speeds. It is dogged by many teething problems & is only useful for a subset of websites at this time. This could change in the years ahead.

AMP logo

Article Spinning

A very borderline technique used to rehash old content by slighty and strategically changing words & phrases to make the article appear like new content.



A link from one document on the internet to another.


What Google started out as on the campus of Stanford University in the second half of the 1990s. This makes Google one of many mega-success stories which started out with another name – joining the likes of Blue Ribbon Sports (Nike) & Brad’s Drink (Pepsi).

Bad Neighborhood

Websites which contain terms or content related to things like dangerous, adult, harrassing in nature, hateful, fake news or otherwise universally undesireable content are seen as bad neighbourhoods & links from them should be disavowed. Additionally you should not link to them (if you have to for whatever reason I’d recommend using rel=nofollow at a minimum).

Black Hat SEO

Activities that search engines do not approve of which could boost a website’s search engine rankings. These include: Content Automation; doorway pages; keyword stuffing; negative SEO); manipulative redirects; cloaking (hidden text or links); link schemes/farms/wheels/networks/manipulation/buying; guest posting schemes; article spinning; markup spam & automated search queries.

Bounce Rate

The percentage of visitors who leave your site before viewing a second page or interacting with your site further. The lower the better & the higher the worse.

Broken Link

A link that directs a visitor to a non-existent resource. This can be due to a typo or because that resource has been removed from the internet.

Bounce Rate


Canonical Tag

A way of telling search engines which URL is the master copy of a page.


Where the content shown to the search engine crawler is different to that presented to the user. A very big offence in the eyes of Google.

Content is King

The idea that content rather than technical SEO or even off-site SEO is what makes the difference between success & failure in search engine marketing. According to this ethos everything else flows from having high quality & interesting content.

Core Web Vitals

Click-Through Rate

The percentage of users who are presented with your webpage as an option in SERPs who click on your webpage. Although CTRs vary wildly largely due to what else is or isn’t also on SERPs a decent rule of thumb is to aim for a CTR of upwards of 2.5%.

Click-Through Rate


How a search engine bot reads the content of the internet. It is also known as a crawler.


Deep Linking

Linking to specific content on a website, rather than the site’s home page. Getting lots of deep links to your website is a sign your site is valuable beyond merely the homepage and is a defacto quality signal.

Dofollow Link

A link which a search engine crawler or bot does follow because it has not been told not to by the rel=nofollow link attribute. These are generally regarded as more valuable than nofollow links to your site.

Domain Authority

Describes a website’s relevance for a specific area/industry. For example a link from the National Geographic would be considered a link from a site with domain authority if you are a wildlife photographer but not if you were an automotive engineer.

Duplicate Content

Dwell Time

The time a user spends viewing a webpage after clicking a link on a search engine results page.

Dwell Time


Evergreen Content

Content that is likely to always be of use. For example much of wikipedia could be viewed as evergreen content. That is people will likely be interested in biographical information of noteworthy people for years to come.

Exact Match Domain

Domain names that are the exact keywords that you are trying to rank for on Google.

Expired Domains

Domain names that have been registered in the past, but weren’t renewed beyond this registration period.

External Links

Links to a webpage on another website.

Exact Match Domain


  • Featured Snippets – special boxes in search results showing the descriptive snippet first.


Google Cache

Google Disavow Tool

Google Search Console

A set of tools and reports that help measure a site’s Search traffic, performance & issues.


Google use several different crawlers or bots to read the content of the internet but the phrase Googlebot is used as a catch-all for the most part to denote all Google crawlers.



H1-H6 headings

Headings of decreasing importance which are used as a way to make a hierachy of information within written text.

Hidden Content

The practice of showing content to search engine crawlers but not to human visitors. This practice is highly discouraged by search engines.


The language tag used to identity different translations of the same website or webpage.

HTML Sitemap

A sitemap for human visitors to be able to navigate your entire website from one page. Or, at the very least, the most important pages on your website on one page.

HTML Sitemap

HTTP Status Codes


Hypertext Transfer Protocol Secure. This is a more secure version of HTTP. Upwards of 98.5% of Page 1 Google search results globally are from webpages which use HTTPS (as opposed to the less secure HTTP).


Image SEO

That subset of SEO techniques specifically for images. Includes image file size minimisation; file formatting; alt tags; descriptions & file titles.

Internal Linking

Linking between pages on the same website.

Intrusive Interstitials

Inverse Document Frequency

A statistic to show how important a word is within a collection of words.

Inverse Document Frequency

IP Address

A numerical label that is connected to a computer network that uses the Internet Protocol for communication.



The words and phrases which users type into search engines to find what they’re looking for.

Keyword Cannibalization

When multiple webpages from the same website are competing for the same keyword thereby effectively lowering that website’s chances of ranking prominently for that keyword.

Keyword Density

How often a keyword is used as a percentage of the total words used in a given piece of content. Whilst there are no exact guidelines a good rough number is never to exceed 3% for a given keyword.

Keyword Difficulty

How hard, in relative terms, it is to rank for a given keyword.

Keyword Stuffing

Overuse of a keyword for the purposes of ranking well on search engines which will almost always have the complete opposite effect (certainly with modern search engine algorithms which are too sophisticated to fall for this crude form of manipulation).

Keyword Density


Latent Semantic Indexing

Is a way for search engines to interpret the meaning of words even if they are described using different words. For example a modern search engine is able to rank a page about [holiday rentals] for search terms such as [b&b] or [guest houses] even though they use different wording to describe basically the same thing. This makes it less necessary for you to describe your content in precisely the same terms as people search for it.

Link Exchange

Outdated technique whereby websites would agree to link to each other to boost both site’s chances of ranking well on Google. Google took measures to neutralise this practice a good decade ago.

Link Hub

Link Text

The text that a user clicks on when following a link. Also known as Anchor Text.


Content that entices people to link to it.

Local SEO

Long Tail Keywords

A phrase that is normally made up of three or more words. They are more specific than Short Tail (generic) keywords and, although, they have lower search volumes individually taken as a whole they actually constitute the majority of web searches in many sectors.

Long Tail Keywords


Meta Description

An HTML tag that summarises a page for both users and search engines.

Meta Keywords

Now disregarded set of keywords webmasters could previously use to describe their content to search engines. Deemed too open to abuse to be of any ranking use to search engines.

Meta Title

Defines the title of a page. Very important Google ranking signal that used to be an extremely imporant ranking signal.

Meta Description

Mobile First

Means placing design & SEO for mobile devices at a premium.

Mobile Friendly



Negative SEO

Nofollow Links

Links which webmasters have told search engines they do not want them to follow. This is often because the webmaster does not want to vouch for the reputation of the website they are linking out to.

Nofollow Links


A way to tell search engine crawlers (bots) that you don’t want search engines to index. Examples might include thin content or outdated content.


Off-Page SEO

Actions that take place off your website to increase your standing in search engines.

On-Page SEO

Activities and interventions made on the page/website itself which improve a sites compliance with Google’s (and other major search engine’s) best practices guidelines and improve the site’s visibility via organic search.

Organic Search

The free or merit based portion of search engine results.

Orphan Pages

Webpages that are not linked to from anywhere else on your website. An HTML sitemap/navigational page are good ways to ensure that this doesn’t happen on your website although only having webpages that are important enough to (and are) linked to by other pages also helps (in multiple ways) too.


Page Speed


A link analysis algorithm which uses the number & quality of inbound links to rank webpages. Google stopped updating the PageRank toolbar some years ago.


A page being loaded in a web browser.


The process of separating content into distinct pages.


A URL that you want to remain unchanged indefinitely. This allows you to gain from inbound links to that URL for a longer time.

Pillar Pages

A page that covers all aspects of a topic without going indepth.

pillar page

Pogo Sticking

When a user visits 2 or more different search results to get the information they need from a search. This is a signal to Google that their search results are not meeting user’s needs & might need to be rethought.

Private Blog Network

A network of, generally unrelated, websites that are used to try to build backlinks to a single website. Tactic has largely been neutralised by Google.


Removing low quality webpages in order to improve the overall quality of a website. Low quality webpages are pages that add little to no value to the user.




robots txt


Searcher Intent

The purpose of a search. So when someone types in [liverpool] what do they mean? Are they asking for information about the city of Liverpool or are they looking for information about the world famous football team?

Search Term

Search Volume

How many searches are made for a given search term. Usually stated in a per month basis averaged over 12 months to correct for seasonality.


The strategic distribution of viral content in Social Networks. I like to call this “drop it where its hot”. The page where you distribute the content within a social network need not be your or your company’s page merely where it is likely to be seen by a large number of potentially interested parties.

Search Engine Marketing

In simple terms SEO, PPC & social media marketing along with content marketing.

Semantic Search

The ability of a search engine to consider contextual meaning of phrases. For example a search for [loft conversion specialists] might return a result for a page that doesn’t even mention the words specialist or even conversion but rather extension and builders. Because they mean very similar things Google and other search engines are capable of including such pages in search results even though they don’t use the exact same wording. I would say that this is an ability which has continually improved since about 2008. Prior to this you were best advised explicitly stating your content in the same words as people were likely to search for it in at all times. Part of how Google achieve this is by making associations and through structured data.

SEO-friendly URLs

URLs that designed to be helpful to both users and search engines. They should be in words and be both concise yet informative.


Search Engine Results Page. The page a search engine returns when a user makes a search.


Social Sharing

Links shared via social networking websites.

Soft 404

A URL for a page that shows the user a page that does not exist but also a 200 (success) status code.



Strong and Bold Tags

Bold text is a minor (very minor) ranking signal that dates back in Google history to The Anatomy of a Large-Scale Hypertextual Web Search Engine by Sergey Brin and Lawrence Page.


Term Frequency

How often a term is used in a document.


Term frequency–inverse document frequency.

Thin Content

Content lacking in text volume and/or substance/value.


The data sent and received by visitors to a website excluding data sent to or received by bots.

Thin Content Google Penalty


Universal Search

URL Hijacking

URL Slug

The part of a URL or link that comes after the domain extension.


User Signals

User-Generated Content


Video SEO

Optimising videos, including Youtube videos, for search engine prominence.


The shape and dimensions of the viewing area on a device.

Voice Search

Searches made by voice. Growing in importance, especially among teenagers.

Voice Search


XML Sitemap

A document listing all pages on a website to give search engines an overview of all content. Whilst HTML sitemaps can be viewed as “nice to haves” the XML sitemap should be viewed as a must-have.

XML Sitemap
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