I'd go out on a limb to suggest that many first time HTML classes start with this on the board...
That first lesson will center around this single construct, starting with an introduction to Standard General Markup Language and the longstanding convention that has applied since the first word processor came into being. It was that process, and the needs it had to fill, that of document creation that lead to the creation of markup.
Markup is the simple noun that identifies what our process embeds in the textual content of the document, which is unseen by the end user. Before there were word processors there were only typewriters and dot matrix printers. All type for the most part looked the same and recognized by the organization, ordering and grouping, and headings; mustn't forget headings.
The way a document reads will be cast into the organization and audience for which it is intended. An essay, screen play, poem, report, citation, and so forth will have its own conventional dictates of form and style. Word processors gave authors (and secretaries) the power to construct stunning documents. Markup was behind it.
In the early goings, that markup might have been manually inserted when preparing the document for publication. You see, once a word processor is brought into the picture, there is no longer any print to paper going on while we type. Everything is saved in memory and/or to disk before printing. The parsing engine of the word processor combined with the print drivers of the printer then render desktop published documents.
Even in those early days before most users of this site were even born, markup was the king of digital publishing. It also filled the need in data storage that made spreadsheets possible. XML is the language of data sheets. The ML stands for Markup Language.
It would not have come as any surprise that when the internet first came into being that the language to adapt to the World Wide Web would be HTML. It was not all that new as a markup language and it supported a concept that went back all the way to HyperCard, a system that, to me anyway introduced links.
And, it used a markup called HyperText. Today, that is the HT in HTML, and we have the linking system that was inherited from that early technology. It made creating and standardizing the WWW so much easier.
The more accurate history is out there if one cares to study up on it.
So here we are in our first HTML class and what have we put down on paper? Hopefully a lot if the professor is a good lecturer. Now go home, and mark up those notes.