Biologically, an adult is a human or other organism that has reached sexual maturity. In human context, the term adult additionally has meanings associated with social and legal concepts. In contrast to a "minor", a legal adult is a person who has attained the age of.
Should it be just "adult" or "adult people"? I think the idiomatic phrase is "Listen, we're all grown-ups here", but "we're all adults here" is fine too. I don't think we ever use 'adult people'.
Adult definition: An adult is a mature, fully developed person. An adult has reached the age when they are | Meaning, pronunciation, translations and.