quais

Quais is the plural form of the Portuguese interrogative pronoun and adjective qual, meaning "which" or "what." It is used in questions to select one or more items from a defined set of possibilities. The singular form is qual and is used for both masculine and feminine nouns; quais marks the plural.

In usage, quais tends to appear when the speaker expects a specific answer drawn from a known group. Examples include “Quais são os seus livros favoritos?” (Which are your favorite books?) and “Quais desses filmes você recomenda?” (Which of these movies do you recommend?). The choice between qual/quais can depend on whether the question implies a limited set or a broader inquiry; qual is used in both singular and plural when the context is more constrained or when asking for one item, while quais is typical for multiple selections from a given group.

Grammatical notes: Qual and quais do not change for gender in the plural form, unlike some other adjectives in Portuguese. The word can introduce a variety of question types, including asking about identity, category, or selection, often followed by a form of ser or another verb, as in “Quais são seus planos?” or “Quais tipos você prefere?”

Etymology traces qual to Latin qualis, meaning “of what kind,” evolving into the modern Portuguese form qual and its plural quais.

See also: qual (singular), que (another interrogative in Portuguese), quays (note: in French, quais means “quays,” a separate etymology and meaning).