algún

Algún is a masculine singular determiner used before a masculine singular noun to mean some or any, depending on context. Its form changes to alguna for feminine singular, and to algunos or algunas for masculine or feminine plural nouns. The accent on ú in algún marks the standard stress pattern and differentiates it from related forms when written.

Usage and scope

Algún is typically used in affirmative contexts to indicate an unspecified, non-exhaustive quantity. It precedes the noun it modifies, as in algún día, algún libro, or alguna idea. When referring to multiple items, the corresponding plural forms son: algunos libros, algunas ideas. Algún is not used before plural nouns; in those cases, muchos, varios, or the plural determiner algunos/algunas are used.

Pronoun use

Alguno, alguna, algunos, and algunas function as pronouns in addition to their adjective use. For masculine singular, some people use uno or alguno as a pronoun; for example, ¿Tienes alguno? “Algunos de ellos” can function as a pronoun phrase meaning “some of them.” The choice between adjective and pronoun forms depends on whether a noun is explicit or omitted.

Negation and contrast

In negative contexts, the counterpart is ningún (before masculine singular nouns) or ninguna (before feminine singular nouns). For example, No tengo ningún libro means “I have no book,” whereas with a positive sense you would say Tengo algún libro.

Common expressions

Algún día (someday), algún lugar (somewhere), alguna vez (ever, sometimes), and de algún modo (in some way) are common collocations showing its versatility beyond a simple determiner.