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40 Essential SEO Terms and Definitions

Nena Vuckovic
40 Essential SEO Terms and Definitions

If you’re looking to learn more about search engine optimization, it might be too much to understand everything at once. SEO terms can be complex, and the uninitiated might need to spend too much time searching for the meaning behind SEO terminologies.

Here, we have a list of technical terms you might encounter during your research. Naturally, we all know what the SEO acronym means, but there are other less common terms you might want to get familiar with.

Chapter 1: Basic SEO Terms

The first part of the SEO glossary lists basic SEO terms you might encounter.

  • Algorithm — It is a sequence of instructions a program performs in order to complete a task or solve a problem. In SEO, an algorithm is a process search engines take to determine the quality and relevance of a website and its content. Experts need to know how the algorithm works to improve the ranking of a website.
  • Black hat — The term describes SEO practices that aren’t allowed or that violate webmaster guidelines. While they aren’t illegal, a person using them might get penalties that could affect their overall ranking in the search engine result pages.
  • Browser — It is a program used to access the internet. The most popular browsers today are Google Chrome, Mozilla Firefox, Opera, Safari, and others. When a user wants to access the information on the internet, the program will retrieve the resources required to render the page on the device.
  • Crawling — Crawling is a process used by search engines that helps them discover webpages. Crawlers/spiders will visit the page and analyze the content on it. They will also check all the relevant links and verify the relevance of the content (including the quality of links).
  • Featured snippets — A featured snippet is an organic answer box that may appear at the top of the search results. In this case, the snippet will come before the link, and the user will get a chance to read the short description of the link.
  • Image carousels — Image carousel is a gallery that may appear on a search engine result page, and it is relevant for the keyword or phrase a user has searched for. You can scroll the images in the carousel from left to right.
  • Indexed/de-indexed — When a web page is indexed, that means that users can find it using search engines. Similarly, de-indexing means that the URL (or even the entire domain) is removed from a search engine. There are numerous reasons why this might happen, and the most common one is a penalty for violating terms and conditions.
  • Index — Index is a database collected and created by crawlers, and it contains all websites and pages that search engines find appropriate and relevant. Indexing is the term used for the process of crawling, organizing, and collecting relevant data from websites.
  • KPI — KPI or key performance indicator is a form of performance measurement. It is a value that shows how well the activity or project is progressing towards its goal. The goal or success can be anything, and it mostly depends on the company and the task at hand.
  • Organic — The term organic or natural describes the type of practice through research and improvement of the content and website. It usually means that the website has earned a place on the search engine list. Organic is also the opposite of paid advertisements and campaigns.
  • Search engine — A search engine is the software designed to help users find the content they need. After a user enters a keyword or a phrase, the engine will list relevant pages for the query. The most popular search engines today are Google, Yahoo, Bing, Baidu, Yandex, and others. However, Google is responsible for more than 80% of global searches.
  • SERP — SERP is among the most important SEO abbreviations, meaning search engine result page. It is the first page a user will see after they enter the keyword or a phrase in the search engine. Here, they will find the most relevant web pages based on their entry. There is organic search (or natural) and sponsored search, which is achieved through advertising and paid promotions.
  • Traffic — Traffic is a term that signifies the number of visitors during a certain period of time. Some measure the relevant traffic on a monthly basis, but it can be any other period (including total traffic). Besides normal or natural traffic, there is also fake traffic, which represents bots. The presence of bot traffic can affect rankings in SERP.
  • URL — Uniform resource locator or URL is commonly known as the web address. It shows the location of the resource, for example, a website. URL also specifies the protocol, such as HTTP, HTTPS, FTP, and others. Most browsers display the address or URL above the page.
  • White Hat — White hat is the term used to describe practices that comply with the webmaster guidelines. The term is the opposite of black hat.

Search Engine Optimization

Chapter 2: On-Site Optimization

  • ALT text — Another name for it is alt attribute, and it is an additional text used to describe an image on the website. The text should act as an alternative in case a user is not able to see the image. You can see it in the HTML and if you hover the mouse over the image.
  • Anchor — Anchor or anchor text is an important part of on-site optimization. The anchor text is the visible text that’s often blue and underlined. In the first sentence of this definition, you can see what the anchor text looks like on the page, and it links to another page (points to a hyperlink).
  • Duplicate content — Duplicate content is any type of content that appears in more than one place on the internet. In this case, “the place” is any address with a unique URL. It also counts if the same content appears on different pages within the same address. Having the same content as other websites doesn’t result in a penalty, but it can affect the search results.
  • Keyword — Keywords are words or phrases that users type into the search engine in order to find information. For the majority of people, keywords are the same thing as query or Google search. Keyword research is an important part of the SEO process.
  • Meta description — Meta description is an HTML element that webmasters use to describe the content of a page or website. Search engines can often use meta descriptions with the link to show a snippet of the page they are showing. On Google, a meta description is under the link, and it should be no longer than 160 characters.
  • Thumbnails — Thumbnail is a smaller version of the media located on the website. Both pictures and videos can have thumbnails, and it is an excellent way to allow users to get a preview of full-size media. Thumbnails exist to reduce the size of the page and improve the loading speed. If a user is interested in seeing more, they can click on the thumbnail to access the full version of the media.
  • Sitemap — Sitemap is a list of all URLs, pages, media, and videos on the website, and crawlers use it to discover and index the content of the website easily. The sitemap acts as a roadmap for bots, and it can help the website rank higher.
  • Tags — Tags are HTML elements. They can provide the necessary info to the search engines, which might affect the rankings. There are title tags, meta description tags, heading tags (H1–H6), image alt text, etc.

Chapter 3: Technical Optimization

  • Backlinks — Backlinks are hyperlinks on other websites that point towards your site. Search engines use backlinks as a form of validation based on the relevance of the websites using them. The bigger the website that points to you, the more SEO points you’ll get.
  • Conversion rate — This term describes the number of conversions compared to the total number of visits. If a website has 1,000 visits and makes 500 sales, the conversion rate would be 50%. Conversions can be anything from signing up for a newsletter to purchasing something from the online store.
  • CSS — CSS or Cascading Style Sheet is a code used for describing the design of the webpage written in HTML. CSS is “in charge” of fonts, layouts, colors, etc. It can also enable the separation of content and presentation, which can improve the stability of the website.
  • DNS — DNS or domain name server is in charge of linking domain addresses to IP addresses. Essentially, it is a naming system for services, computers, and other resources connected to the internet.
  • Google Analytics — It is a free tool that website owners can use to get an insight into traffic, interaction, and engagement on their website. Google Analytics can also show what channels the visitors are coming from or even the conversion rate. Currently, it is the most popular analytics tool.
  • HTML — HTML or hypertext markup language is a programming language designed for the use in web browsers. CSS and JS often accompany it, and the majority of pages utilize HTML.
  • IP address — IP or internet protocol address is a unique sequence of numbers that represent the address of a website. For almost every IP address, there is a corresponding domain we use to access the website and its content.
  • JavaScript — JavaScript, also known as JS, is a programming language. Both server-side and client-side use it, and the idea behind it is to make web pages more interactive. While HTML and CSS are used for the structure and style of a website, the goal of JS is to make interactive content that will be engaging for an end-user.
  • Lazy loading — Lazy or asynchronous loading is a process of deferring initialization (or loading) of an object until it’s needed. It is a common way of improving the performance and speed of a website, and experts mostly use it for images. The opposite of lazy loading is eager loading.
  • txt — It is a text file created by the webmaster that determines which pages should be indexed by crawlers or bots. Robots.txt is a set of instructions, and it can also point to pages that crawlers shouldn’t index in the process.

Technical SEO

Chapter 4: Off-Site SEO and Execution

  • Bots — Bots are otherwise known as web crawlers or spiders. They are programs which index the pages on the internet. These programs index the content of the website, which helps users search for the pages more efficiently.
  • Bounce rate — Bounce rate is the percentage of user visits that did not result in any secondary action. In essence, it means that someone visited the website only to leave without checking out other pages or content the website has to offer.
  • Cache/caching — Cache is a software component stored on the device a person uses to access a webpage. It contains data from previous sessions. Browsers use cache to make pages load faster, but it only works for websites the user has visited already. Caching will reduce loading times for frequently visited webpages.
  • Internal links — Internal links are the opposite of backlinks. The reason they are called internal is that they are located on one website and point to other pages of the same website. The difference between the two is that backlinks point from one website to the other. Internal links also use anchors to point to other pages of the website.
  • Link building — Link building is a process of creating backlinks. Since, by their definition, backlinks appear on other websites, the term means earning links on other pages that lead to your website. This will also earn you the authority on search engines and improve the rankings of your website. Link building is an important part of the off-page SEO
  • Ranking — Organizing results in the search engine based on their relevance and importance. Search engines will analyze the query and list the closest website to the phrase or keyword the user has entered.
  • Rendering — Rendering is a process of translating the code from the website into a viewable page. This includes media, images, sounds, any visual element, like menus, and anything else that may appear on the page. Some browser engines will begin the process of rendering before all resources are downloaded to improve the speed.


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We can build on your idea and provide solutions to take your business to the next level.
Please fill in this form to start the process.