Ain't is a colloquialism and contraction for "am not", "is not", "are not", "has not", and "have not" in the common English language vernacular. In some dialects ain't is also used as a contraction of "do not", "does not", and "did not". The usage of ain't is a perennial subject of controversy in English. Widely used by many people, and found in most dictionaries, its use is often considered to be informal, nonstandard, or improper.

"Ain't ain't in the dictionary, because ain't ain't a word" That is what we were taught in school. But to answer your question, "ain't" is a colloquial version of "isn't" or "is not" whilst "aren't" is a proper contraction for "are not". Sorry - wrong place

It's a colloquial word meaning: "isn't" and "aren't".

I means the same thing as arent but its kind of rude and stupid obsolete version.

am not, has not, have not, is not, are no