—adj.
1 used or done or held in accordance with rules, convention, or ceremony (formal dress; a formal occasion).
2 ceremonial; required by convention (a formal call).
3 precise or symmetrical (a formal garden).
4 prim or stiff in manner.
5 perfunctory, having the form without the spirit.
6 valid or correctly so called because of its form; explicit and definite (a formal agreement).
7 in accordance with recognized forms or rules.
8 of or concerned with (outward) form or appearance, esp. as distinct from content or matter.
9 Logic concerned with the form and not the matter of reasoning.
10 Philos. of the essence of a thing; essential not material.
—n. US 1 evening dress.
2 an occasion on which evening dress is worn.
Derivatives:
formally adv. formalness n.
Etymology: ME f. L formalis (as FORM)
Useful english dictionary. 2012.