certas

Certas is the feminine plural form of the Portuguese adjective certo/certa, meaning "certain" or "particular." It is used to modify feminine nouns and to refer to a subset of items known to the speaker or to indicate that specific conditions, rules, or choices apply. In both European and Brazilian Portuguese, certas can appear in formal and informal contexts.

Etymology and grammar: The word derives from Latin certus, meaning "certain" or "sure," through the evolution of Latin and Old Portuguese into modern Portuguese. The ending -as marks the feminine plural, so masculine plural would be certos and feminine singular would be certa.

Usage and nuance: Certas is commonly found with feminine nouns such as pessoas, regras, exigências, condições, and opções. Examples include: Certas pessoas chegaram atrasadas. Para participar, você precisa cumprir certas exigências. Existem certas regras que se aplicam a todos. The sense conveyed by certas emphasizes a defined subset or particular items that are recognized as relevant or appropriate, in contrast with more indefinite terms like algumas or qualquer.

Variations and related terms: Certas contrasts with masculine forms (certos) and with related words such as certa (feminine singular), certeza (noun meaning "certainty"), and certificar-se (to certify). While certas can function in a sentence as a determiner or modifier, it does not operate as a standalone pronoun; the noun it modifies carries the reference.

See also: In Portuguese, other forms of the same root include certo, certa, certeza, and certificar. The use of certas is common across dialects, with nuance depending on formality and regional preference.