Articles: el, la, un, una; al and del

What it is

Articles are the small words in front of a noun. Spanish has definite articles (el, la, los, las = "the") and indefinite ones (un, una = "a / an"; unos, unas = "some"). They agree with the noun in gender and number: la casa, los libros, una mesa, unos amigos.

How to form it

Only two contractions. When a (to) or de (of, from) meets el, they always merge:

Every other combination stays as two words: en el, en la, con el, por el, de la. Two cases never merge: a name that includes El (Gabriela es de El Salvador) and the pronoun él, "he" (el carro de él, his car).

El agua. Feminine nouns that begin with a stressed a- or ha- take el and un in the singular, so that two a sounds don't collide: el agua, el aula, un águila. They are still feminine: el agua fría, las aguas, las aulas. With an unstressed a, nothing changes: la amiga, la avenida.

Lo is not "the". The masculine article is el. Lo goes before adjectives (lo bueno, "the good thing") or works as a pronoun, never before a noun.

When to use it

• The definite article points to something known or unique (la capital de Chile, el sol) and to things in general: El café de Colombia es famoso. With likes it is obligatory: Me gusta el café, a pattern you will practise with gustar.
• The indefinite article brings in something new, or one of many: Un café, por favor. Unos / unas means "some" and, before a number, "about": unos amigos de Lima, unas diez personas.
• Days take only the article: el lunes = on Monday, los lunes = on Mondays, every week.
• People with a title: use the article when you talk about them and drop it when you talk to them: La señora Pérez es de Quito, but Buenos días, señora Pérez.
• No article: with ser + a job (Soy enfermera), with most countries (Soy de Brasil, de Chile), after otro (otro café) and in en casa, "at home".

• Un café y una empanada de queso, por favor.A coffee and a cheese empanada, please.first mention: un, una
• La sopa del día es de pollo.The soup of the day is chicken.de + el = del
• Para mí, el pescado al horno.For me, the baked fish.a + el = al
• La fiesta de Valeria es el sábado.Valeria's party is on Saturday.el + day = on
• Los martes, la clase es en el aula 3.On Tuesdays, the class is in classroom 3.el aula: feminine
• La señora Pérez es de El Salvador.Mrs Pérez is from El Salvador.El is part of the name

Contrasts and traps

• a el, de el: always al, del, in speech and in writing.
• Uno or un? Before a masculine noun, un: un café. Standing alone it is uno: —¿Un café o dos? —Uno.
• "On" with days: El examen es el viernes, never en el viernes.
• Things in general: "Coffee is expensive here" → El café es caro aquí.
• Jobs: Mi papá es médico, without un. The article comes back with an adjective: Es un médico excelente.

If you also speak Portuguese

Portuguese merges almost every preposition with the article; Spanish only has al and del. So no → en el, na → en la, da → de la, dos → de los, pelo → por el. The masculine article is el, never o or lo, and there is no article before possessives or first names: mi casa, Pedro es de Cali.