Reading about TeX/LaTeX online, I'm a little confused as to what it is- isn't it a language? Wikipedia calls is it a typesetting system- and to make matters worse, if I want to use LaTeX, I need to download something like MikTeX which is also called a typesetting system. Why isn't LaTeX just called a programming language, and why isn't there just one installer to download, like with Python?
TeX is too many things to be anything less than a system. It consist of (this and even more):
- programming languages and file type specs: TeX, METAFONT (METAPOST), bib, bst, dvi, ...
- a compiler (tex), actually, more compilers
- typesetter, since the output of the compiler is not just a sequence of the language primitives, but as well the output laid out.
- forks of the compiler (and even of the language): LuaTeX, XeTeX, ConTeXt, ...
- new fonts developed with the system: Computer Modern, Latin Modern, TeX Gyre, ...
- auxiliary tools: bibtex, biber, pdftk
- thousands of packages doing various stuff, not only in the TeX language, but in many other languages around.
And that all is installed in your computer when you get TeXLive or MikTeX. No less general word than "system" can comprise all of this.