The HTML stands for HyperText Markup Language.
What is HyperText?
HyperMedia is a term used for hypertext which is not constrained to be text: it can include graphics, video and sound , for example. Apparently Ted Nelson was the first to use this term too.
Hypertext and HyperMedia are concepts, not products.
What is Markup?
So, HTML is concept of enhancing the visual appearance of the HyperText.