Ambos: Both

English both is one of the most invariable words in the language — no plural, no gender, and the article is optional ("both books" or "both the books"). Brazilian Portuguese ambos/ambas looks like a direct equivalent but behaves quite differently: it agrees in gender, it requires the definite article on the noun, and — most importantly for a learner who wants to sound natural — it is distinctly bookish. In everyday Brazilian speech people reach for os dois / as duas instead. This page covers the grammar of ambos and, just as crucially, when not to use it.

The two forms

Ambos has only a gendered contrast, never a singular (the meaning is inherently dual):

Use ambas when both items are feminine, ambos when both are masculine or mixed. (As everywhere in Portuguese, a mixed-gender pair defaults to masculine: ambos.)

The article rule — ambos os, ambas as

This is the structural surprise. Unlike ambos taking no article itself, the noun keeps its definite article. So you get the sequence ambos + os/as + noun:

Leaving the article out — ambos livros — is a classic error. English speakers expect both to attach straight to the noun (because English allows "both books"), but standard Portuguese inserts the article: ambos *os livros. Think of *ambos as adding emphasis on top of "the two," so the definiteness — and thus the article — stays put.

Ambos is bookish — what BR actually says

Here is the register reality that textbooks often hide. Ambos/ambas is correct, elegant, and common in writing, journalism, and formal speech — but in everyday Brazilian conversation it sounds a little stiff. The natural spoken form is os dois / as duas:

So os dois livros and ambos os livros mean the same thing; the first is what you say to a friend, the second is what you write in a report. A learner who only knows ambos will be understood everywhere but will sound slightly formal in casual settings; a learner who only knows os dois will sound natural in speech but should still recognize ambos in text.

Ambos as a standalone pronoun

Like os dois, ambos/ambas can drop the noun and stand alone, meaning "both of them":

When it stands alone the verb is plural — ambos vieram, ambas são — because the meaning is inherently two people or things.

There is also a useful prepositional pattern: de ambos, com ambas, para ambos, where ambos stands alone after a preposition and still agrees with the (omitted) noun it refers back to.

The fuller, formal phrasing ambos os dois — avoid it

You may occasionally hear ambos os dois ("both the two"). This is redundant — ambos already means "the two" — and is widely considered an error or, at best, heavy colloquial reinforcement. Use either ambos os X or os dois X, not both at once.

Comparison with English

Three differences to internalize. First, English both never changes; Portuguese chooses ambos vs ambas by gender. Second, English makes the article optional ("both the books" / "both books"); Portuguese, when using ambos, makes it obligatory (ambos *os livros). Third — and this has no English parallel — *ambos carries a formal flavor that both does not, so the everyday translation of casual "both" is usually os dois / as duas, not ambos. English speakers tend to over-rely on ambos precisely because it looks like a one-to-one swap for both; in real Brazilian speech it lands as bookish.

Common Mistakes

Key Takeaways

• ambos/ambas = "both," agreeing in gender (no singular form).
• The noun keeps its definite article: ambos os / ambas as
  • noun.
• Ambos is formal/written; everyday BR speech uses os dois / as duas.
• It can stand alone as a pronoun ("both of them"), always with a plural verb.
• Avoid the redundant ambos os dois; use ambos os X or os dois X.