SEO Glossary: Common Search Engine Optimisation Terms Explained

By Shane Snyman, JWD Website Design Updated 19 August 2026

SEO comes with its own vocabulary, and an agency throwing terms like “backlinks” and “schema markup” at you without explaining them is not doing you any favours. This glossary breaks down the terms South African business owners actually hear most often, in plain English, so you know exactly what you are paying for. If you want the full picture of how SEO works and what it involves, our complete guide to SEO in South Africa is the place to start.

On-Page SEO

The optimisation work you do directly on your own website: your content, page titles, headings, meta descriptions, image alt text, and internal links. It is the part of SEO you have full, direct control over.

Off-Page SEO

The optimisation work that happens away from your own website, mainly earning backlinks from other reputable sites, alongside social media mentions and citations in directories. It builds the authority and trust signals your on-page work alone cannot.

Technical SEO

The behind-the-scenes work that makes sure search engines can actually crawl, understand, and index your site properly: site speed, mobile-friendliness, clean URLs, HTTPS, and no broken crawl paths. Even great content struggles to rank if the technical foundation is broken.

Local SEO

Optimising your website and listings so your business shows up when people search for what you offer in a specific area, like “electrician Sandton” rather than just “electrician”. For most South African small businesses, this is where the highest-intent, ready-to-buy traffic comes from.

Keyword

A word or phrase someone types into a search engine. Good SEO work starts by understanding which keywords your actual customers use, not the terms you assume they use.

Backlink

A link from another website pointing to yours. Search engines treat backlinks as a vote of confidence, a link from a reputable, relevant site carries real weight, while a link from a spammy directory carries little to none and can occasionally do harm.

SERP

Short for Search Engine Results Page, the page of results Google shows after a search. Where your site appears on the SERP for a given keyword is what most people mean when they talk about “ranking”.

Meta Description

The short summary text that appears under your page title in search results. It does not directly affect rankings, but it strongly affects whether someone actually clicks through, think of it as your ad copy for organic search.

Title Tag

The clickable headline shown in search results for a page. It should be unique per page, contain the page’s target keyword, and stay under roughly 60 characters so it does not get cut off.

Alt Text

A short written description attached to an image, since search engines cannot “see” a picture the way a person can. It matters for both SEO and genuine accessibility for visitors using a screen reader.

Schema Markup

Code, usually in JSON-LD format, added to a page that explicitly tells search engines and AI systems what your content actually is, a business, a product, an FAQ, a review. It can unlock rich results like star ratings in search listings, and it is increasingly important for AI systems deciding what to cite. Our schema markup guide covers this in more depth.

Core Web Vitals

Google’s specific set of page experience measurements: how fast your main content loads, how quickly the page responds to interaction, and how visually stable it is while loading. All three are used as ranking signals.

Crawling

The process where a search engine’s automated bots visit your pages to discover what is on your site. A page that cannot be crawled, because of a technical block or a broken link path, cannot be indexed or ranked.

Indexing

Once a page has been crawled, indexing is Google adding it to its searchable database. A page can be crawled but still fail to be indexed if Google judges it low quality, duplicate, or not worth including.

Domain Authority

A third-party metric (not an official Google score) estimating how likely a whole website is to rank, based mainly on the quantity and quality of its backlinks. Useful as a rough guide, not a number to obsess over.

NAP Consistency

Short for Name, Address, Phone number. Keeping these identical everywhere your business appears online, your website, Google Business Profile, directories, prevents confusing local search signals and weakens your local rankings when it slips.

E-E-A-T

Experience, Expertise, Authoritativeness, Trustworthiness, the qualities Google’s algorithm and human quality raters look for when judging whether content deserves to rank, particularly for topics that affect someone’s health, finances, or safety.

AEO

Answer Engine Optimisation, the practice of structuring content so AI systems like ChatGPT, Perplexity, and Google’s AI Overviews can find, understand, and cite it correctly, not just classic search engines. Our AEO guide goes into this in full.

Canonical URL

The version of a page’s URL that you tell search engines is the “official” one, used to prevent duplicate content issues when the same content is reachable at more than one address.

301 Redirect

A permanent redirect from an old URL to a new one, telling both browsers and search engines that a page has moved for good. Used correctly, it preserves the search value a page had built up when its address changes.

Want the fuller picture behind any of these terms? Our complete guide to SEO in South Africa walks through how they all fit together, or request a quote and we will explain exactly what your business needs in plain English, no jargon left unexplained.

Frequently Asked Questions

What is the single most important SEO term to understand?

If you only learn one, understand the difference between on-page and off-page SEO, since almost every other term falls under one of those two categories. On-page is what you control directly on your site, off-page is what you earn from the wider web.

Do I need to understand all these terms to hire an SEO agency?

No, but knowing the basics helps you tell a genuine strategy from a vague sales pitch. If an agency cannot explain what they mean by a term in plain English when you ask, that is worth noticing.

What is the difference between a keyword and a search query?

They are closely related. A keyword is the general term or phrase you are targeting in your content, a search query is the exact words a real person typed into the search box. People rarely search in perfectly matched keyword phrases, which is why good content covers a topic naturally rather than repeating one exact phrase.

Why does Core Web Vitals matter if my site already looks fine to visitors?

A site can look fine while still loading slowly or shifting content around as it loads, both of which Google measures directly and both of which frustrate real visitors even if the finished page looks acceptable once fully loaded.

Where can I learn how all these SEO terms fit together in practice?

Our complete guide to SEO in South Africa covers the full picture, on-page, off-page, technical and local SEO, how long results take, and what it costs, written for South African business owners rather than SEO professionals.