formais

Formais is the masculine plural form of the Portuguese adjective formal. It describes things that belong to a form, follow established rules or conventions, or conform to official, ceremonial, or regulated standards. The feminine plural form is formals, and in practice formais is used with both masculine and feminine nouns in the plural (for example, roupas formais).

The term has broad usage across domains. In everyday language, it contrasts with informal: linguagem formal (formal language) versus linguagem informal (informal language); roupas formais (formal clothes) versus roupas informais (informal clothes). In institutional contexts, formais can describe procedures, documents, or events that require adherence to prescribed protocols, such as procedimentos formais or documentos formais.

In academia and science, formais is common in expressions like linguagens formais (formal languages), gramáticas formais or lógicas formais (formal logic). In computer science and mathematics, formal methods (métodos formais) refer to rigorous, mathematically based techniques used for specifying and verifying systems. The root is Latin formalis, from forma, meaning form or shape, reflecting the sense of adherence to a defined structure.

Usage notes: formais functions as an adjective and does not change for number beyond agreeing in gender and plural with the noun it modifies. It is typically paired with nouns that denote standards, attire, communication, or methodologies, and serves as a counterpart to informal in describing registers, procedures, and approaches. See also language formality, formal languages, and formal methods.