Meaning of formal
Definition of formal
(adj)
being in accord with established forms and conventions and requirements (as e.g. of formal dress); "pay one's formal respects"; "formal dress"; "a formal ball"; "the requirement was only formal and often ignored"; "a formal education"
(of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms; "the paper was written in formal English"
logically deductive; "formal proof"