Question

what is the meaning of ! in math

Answer 1

! means factorial
n! means n factorial

Answer 2

Mathematics is a language, in that it allows us to express ideas and notions that are hard or impossible to communicate otherwise. Music is a language in precisely this sense, too.

Mathematics is far more than just a language, though. It is more than a way of communicating and expressing ideas. It has theorems, truths, proven facts about things. That is something that languages simply lack.

Those theorems are expressed in mathematical language, but they aren't merely that language. This is why I feel that "mathematics is a language" doesn't quite capture what math is.