What is HTML?
HTML stands for Hypertext Markup Language. It is a language used to create webpages. Simple. The current webpage that you're viewing is also created using HTML (and then embellished with other things such as CSS and JavaScript but that's the talk for another day).
Being a bit more technical, HTML helps you define three things: content, its structure, and its meaning. Let's dive into each one...
By "content," you specify literally what shows up on the webpage, for e.g. the text "Hello world." or a recipe for a classic pound cake (delicious!).
By "structure," it means that you specify what comes inside what. For example, a section contains a heading, which itself contains a quote. In other words, you specify how the content is structured out.
By "meaning," you specify what that content means. For example, a piece of text might represent the main heading or a quote by some famous personality — HTML helps you define what is that exactly.
Dissecting the meaning of "HTML"
If we dissect the cool phrase "Hypertext Markup Language", we essentially get two terms: hypertext and markup language. It's worthwhile knowing what they both mean.
What is hypertext?
Hypertext is text that is interactive. It contains links — formally referred to as hyperlinks — to navigate to related pieces of text. That's exactly what the word "hyper" represents here.
Using hypertext, we can skip past the normal reading flow of text and rather jump to other pieces of text. For example, when you click on a link on a webpage to go to some other section on the webpage, you're basically jumping past text.
HTML, as you'll soon see, also supports the idea of hyperlinks and is rightfully an eloquent hypertext system.
What is a markup language?
A markup language is used to mark up text, i.e. wrap the text with something to give it a special meaning.
For instance, you might wrap up a piece of text to make it explicit that it's a greeting to the person reading the text, or maybe it's a warning message, and so on.
There are many markup languages in use today, for e.g. XML, Markdown, LaTeX, and SVG, to name a few.
Markup languages are NOT programming languages!
It's important to note that a markup language is NOT a programming language, per se. It doesn't have any of the logical constructs that are otherwise commonly present in a programming language (like JavaScript or Python) such as statements, conditionals, loops, functions, etc.
HTML source code is not executed (only a program is executed). So please don't call HTML a programming language! It's not one!