formal

adjective

• 1done in accordance with convention or etiquette; suitable for or constituting an official or important occasion:a formal dinner party
• (of a person or their manner) strictly conventional: he is formal in manner and clothing
• having a conventionally recognized form, structure, or set of rules:he had little formal education
• of or denoting a style of writing or public speaking characterized by more elaborate grammatical structures and more conservative and technical vocabulary.

• 2officially sanctioned or recognized:a formal complaint

• 3of or concerned with outward form or appearance as distinct from content:I don’t know enough about art to appreciate the purely formal qualities
• having the form or appearance without the spirit:the committee stage would be purely formal
• relating to linguistic or logical form as opposed to function or meaning.

noun

• an evening dress: cocktail parties every night so the ladies can show off their formals
• an occasion on which evening dress is worn: the college will be hosting their annual formal on February 6