HTML stands for Hypertext Markup Language
Programming languages are called languages because it's similar to learning a new language to speak. Some are easier, some are harder, and some are very similar to others.
There are many programming languages, being a coder means that you will keep learning new code and languages throughout your life, you fall behind if you just stop at one or two but as a hobby this is okay :)
HTML is the language you need to know before learning any other coding language because it's what gives structure to your application, game, website, or whatever. I once read someone compare it to the bones of your body, they're the bottom layer, they hold you up, they're the structure.
HTML is awesome, because surprisingly you can do so much stuff with it!
YOU ARE READING
The HTML Book [html survival guide]
Non-FictionLearn it with me :) You can request I make another book for CSS and I might 🤷🏼♀️