O Pedro compra um guarda-chuva no mercado.

In European Portuguese, it is very common to put the definite article before a person's name: o Pedro, a Maria.

This does not translate naturally as the Pedro in English. It is just a normal Portuguese pattern.

So:

• O Pedro = Pedro
• A Ana = Ana

In Portugal, this is especially common in everyday speech. In some situations, the article may be left out, but o Pedro sounds very natural.

Comprar is the infinitive, meaning to buy.

In the sentence, the verb has to match the subject O Pedro, which is he / third person singular. So the verb changes:

• eu compro = I buy
• tu compras = you buy
• ele/ela compra = he/she buys

So O Pedro compra means Pedro buys or Pedro is buying, depending on context.

It can mean either, depending on context.

In Portuguese, the simple present often covers both:

• he buys
• he is buying

So O Pedro compra um guarda-chuva no mercado could mean:

• Pedro buys an umbrella at the market
• Pedro is buying an umbrella at the market

If you want to make the ongoing action very explicit in European Portuguese, you often use:

• O Pedro está a comprar um guarda-chuva. = Pedro is buying an umbrella.

Yes, guarda-chuva is a masculine singular noun, so it takes um:

• um guarda-chuva = an umbrella

Even though compound words can look unusual, you still learn their gender as part of the noun. In this case:

• singular: o guarda-chuva
• plural: os guarda-chuvas

So um is used because the noun is masculine and singular.

Because it is a compound noun: it is made from more than one element and is written as one fixed expression with a hyphen.

• guarda-chuva = umbrella

This is just something you learn as part of the word's spelling. Portuguese has many compound words with hyphens, although the rules are not always obvious to learners.

Also notice the plural:

• guarda-chuva → guarda-chuvas

Usually only the second part changes here.

Because Portuguese normally contracts the preposition em with the definite article o:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

So:

• no mercado = in the market / at the market

You would not normally say em o mercado.

Portuguese often uses the definite article where English may or may not use one.

So no mercado means:

• in the market
• at the market

It sounds natural because Portuguese often refers to places with the article.

If you said num mercado instead, that would mean:

• in a market
• at a market

So the choice changes the meaning:

• no mercado = in/at the market
• num mercado = in/at a market

The sentence follows a very common pattern:

Subject + Verb + Object + Place

• O Pedro = subject
• compra = verb
• um guarda-chuva = object
• no mercado = place

So the structure is very similar to English:

• Pedro buys an umbrella at the market.

That makes this sentence quite straightforward for English speakers.

Yes, you can, but it changes the style a little.

• O Pedro compra... sounds very natural in European Portuguese everyday usage.
• Pedro compra... is also possible, especially in more formal, written, or headline-like contexts.

So both can exist, but in Portugal, the version with the article is very common in normal speech.

Mercado usually means market.

Depending on context, it can refer to:

• a traditional market
• a town market
• sometimes a shopping or food market environment

If someone specifically means supermarket, the usual word is:

• supermercado

So no mercado most naturally suggests at the market rather than at the supermarket.

A simple learner-friendly approximation is:

• GWAR-da SHOO-va

A few useful points:

• guar- sounds roughly like gwar
• ch in Portuguese sounds like sh
• chuva sounds roughly like SHOO-va

European Portuguese pronunciation is often more reduced than Brazilian Portuguese, so unstressed vowels may sound less clear than an English speaker expects.

Yes, um guarda-chuva is the normal standard word for an umbrella.

You can also see:

• o guarda-chuva = the umbrella
• um guarda-chuva preto = a black umbrella
• os guarda-chuvas = the umbrellas

So this is the standard everyday noun you should learn for umbrella in Portuguese.

Because Pedro is a proper noun, and proper nouns are capitalized.

• Pedro = name of a person → capital letter
• mercado = common noun → no capital letter

This works much like English:

• Pedro
• market

So the capitalization here is exactly what you would expect.