O cachorro ganhou um petisco.

Ganhou is the simple past (also called the preterite) of ganhar for he/she/it and you (você).

So:

• eu ganhei = I got / I won
• você / ele / ela ganhou = you / he / she got
• nós ganhamos = we got
• eles / elas ganharam = they got

In O cachorro ganhou um petisco, the action is seen as completed: the dog got the treat.

It comes from the verb ganhar.

Ganhar can mean:

• to win
• to earn
• to get / receive

In this sentence, ganhou is best understood as got or received, not necessarily won in a competition.

For example:

• Ela ganhou dinheiro. = She earned money.
• Ele ganhou um presente. = He got a gift.
• O time ganhou o jogo. = The team won the game.

No. That is a very common point of confusion for English speakers.

Depending on context, ganhar can mean:

• to win → ganhar o jogo
• to earn → ganhar salário
• to receive / get → ganhar um petisco, ganhar um presente

So in this sentence, the dog did not necessarily win a treat. It simply got one.

O is the definite article, meaning the.

So:

• o cachorro = the dog
• um cachorro = a dog

Portuguese uses articles very often, sometimes more often than English. In this sentence, o cachorro usually refers to a specific dog that is already known in the context.

You can sometimes omit the article in Portuguese, but here O cachorro ganhou um petisco is the natural standard form.

Um is the indefinite article meaning a or an.

So:

• um petisco = a treat
• o petisco = the treat

It is um because petisco is a masculine singular noun.

If it were feminine, you would use uma instead.

For example:

• um presente = a gift
• uma bola = a ball

Both nouns are masculine, which is why they use:

• o cachorro
• um petisco

A common pattern in Portuguese is that nouns ending in -o are often masculine, though this is not a perfect rule.

Here:

• cachorro → masculine
• petisco → masculine

That affects the articles and also any adjectives that agree with them:

• o cachorro feliz
• um petisco gostoso

In Brazilian Portuguese, cachorro usually means dog in everyday speech, regardless of sex.

Strictly speaking:

• cachorro can mean male dog
• cadela = female dog

But in normal conversation, Brazilians often use cachorro as the general word for dog.

For puppy, a more precise word is:

• filhote
• filhote de cachorro

So in this sentence, cachorro is most naturally understood as simply dog.

Petisco is a small treat, snack, or tidbit.

In the sentence O cachorro ganhou um petisco, it most likely means a dog treat.

But petisco is not only for animals. It can also refer to small snacks for people, especially bite-sized food.

Examples:

• Comprei petiscos para a festa. = I bought snacks for the party.
• O cachorro ganhou um petisco. = The dog got a treat.

So the exact English translation depends on context.

This is the normal subject + verb + object order:

• O cachorro = subject
• ganhou = verb
• um petisco = object

That is very similar to English:

• The dog got a treat

Portuguese word order is often flexible, but this is the most neutral and natural version.

You could change the order for emphasis in some contexts, but the basic learner-friendly pattern is exactly what you see here.

In Brazilian Portuguese, ganhou is pronounced approximately like:

gan-YOH

A more detailed breakdown:

• ganh- contains nh, which sounds like the ny in canyon
• -ou often sounds like oh in Brazilian Portuguese

So ganhou is roughly gan-YOH.

Also, the stress is on the second syllable:

• ga-NHOU

A rough pronunciation for Brazilian Portuguese is:

oo ka-SHOH-hoo gan-YOH oong peh-CHEES-koo

A few important sound notes:

• O before a consonant often sounds like oo
• cachorro has the ch sound like English sh
• the rr in cachorro is pronounced like a Portuguese h-like sound in many Brazilian accents
• nh in ganhou sounds like ny
• ti in petisco sounds like chee in many Brazilian accents, so pe-TCHEES-co is common

This is only an approximation, but it helps you get close.

Yes. Recebeu is also possible.

• ganhou um petisco = got / was given a treat
• recebeu um petisco = received a treat

The difference is mostly nuance:

• ganhou can sound a little more natural when someone is given something as a reward, gift, or nice surprise
• recebeu is a bit more neutral and literally means received

For a dog being given a treat, ganhou sounds very natural in Brazilian Portuguese.

You might hear article omission in some contexts, but O cachorro ganhou um petisco is the normal and most natural form.

Without um, the sentence sounds less standard and less complete in most situations.

So for learners, it is best to keep the article:

• O cachorro ganhou um petisco.

You need to change the article, noun, and verb as needed.

For example:

• Os cachorros ganharam um petisco. = The dogs got a treat.
• Os cachorros ganharam petiscos. = The dogs got treats.

Changes:

• o → os
• cachorro → cachorros
• ganhou → ganharam
• petisco → petiscos if you want plural treats

This is a good example of agreement in Portuguese.