Learn Portuguese (Portugal): Qual é o código postal?

In Portuguese, o que is used to ask for a definition or explanation (like asking "What is a postcode?"). When you are asking for specific information, a detail, or an identity out of many possibilities (like a phone number, a name, or a postcode), you use qual (which translates more closely to "which").

Why is it código postal instead of postal código?

In Portuguese, descriptive words (adjectives) almost always come after the thing they describe (the noun). So, "postcode" is formed by saying the word for "code" (código) first, followed by the describing word "postal" (postal).

Why do we use é here for "is"?

É comes from the verb ser, which is one of the two Portuguese verbs for "to be". We use ser for permanent states, facts, and identities. Since a postcode is a fixed, defining piece of information, é is the correct verb to use.

What does the accent mark on código do?

The acute accent mark shows you exactly which syllable to stress when pronouncing the word. Without it, the normal Portuguese pronunciation rules would place the stress on the second-to-last syllable. The accent tells you to emphasize the first syllable instead: CÓ-di-go.