Why are some functions called 'forms'?

Question

The question is simple: why are some functions called 'forms'? Modular 'forms', bilinear 'forms', differential 'forms', quadratic 'forms', and so forth. It is not concretely a mathematical question but I suppose the origin of the term must be mathematical, so I ask it here.

Thanks for the comment, it seems the question was already answered here: What do mathematicians mean when they say "form"?

and here's another page: Earliest use of the word "form" in mathematics?

Answer 1

See links: What do mathematicians mean when they say "form"?

I like this one: Earliest use of the word "form" in mathematics?

Link to wiki of Plato's theory of forms: https://en.wikipedia.org/wiki/Theory_of_forms