Indefinites
Indefinites are linguistic expressions used to refer to non-specific persons, places, things, or amounts. They contrast with definites, which point to a fixed referent in the discourse. Indefinites can introduce new information, generalize, or convey approximate quantities, and they often interact with context, negation, and questions.
Indefinite articles designate non-specific singular nouns in languages with articles; in English, a and an appear
Semantically, indefinites provide non-specific references and may carry existential readings (there exists someone/something) or non-referential readings
Cross-linguistic variation shows that some languages have articles specifically marking indefiniteness, others rely on bare nouns,