Definite and Indefinite Articles

In English, the definite article is æthe,Æ and the indefinite article is æa,Æ or æan.Æ 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.