In English, the definite article is ‘the,’ and the indefinite article is ‘a,’ or ‘an.’ In Spanish, the articles have four forms, and they must agree with the noun in number (singular or plural) and gender (masculine or feminine):
 

Definite Articles
Masculine	Feminine
el	la (singular)
los	las (plural)

 

Indefinite Articles
Masculine	Feminine
un	una (singular)
unos	unas (plural)

Examples: el aeropuerto, los billetes, la empleada, las oficinas, un hombre, unos dólares, una señora, unas conversaciones.