formal in WordNet English dictionary

1. a lavish dance requiring formal attire
   ball  formal 
   
2. a gown for evening wear
   dinner dress  dinner gown  formal  evening gown 
   

1. represented in simplified or symbolic form
   conventional  formal  schematic 
   
2. refined or imposing in manner or appearance; befitting a royal court
   "a courtly gentleman"
   courtly  formal  stately 
   
3. 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"
   formal 
   
4. (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"
   formal 
   
5. logically deductive
   "formal proof"
   formal 
   
6. characteristic of or befitting a person in authority
   "formal duties"; "an official banquet"
   formal