Learn Portuguese (Portugal): Qual é o seu nome?

In English, we ask 'What is your name?', but in Portuguese, you use Qual (which) when asking for specific information from a category, like a name, phone number, or address. Think of it as asking 'Which name is yours?'. You generally only use O que for 'What' when asking for a definition or explanation.

Why is there an o before seu? Doesn't seu already mean 'your'?

Yes, seu means 'your'. However, in European Portuguese, it is standard to put a definite article (o or a) before a possessive word. Since nome is a masculine word, we use the masculine article o to make it o seu nome (literally 'the your name').

I thought seu meant 'his' or 'her'. Why does it mean 'your' here?

You are right that seu can mean 'his' or 'her'! In Portuguese, the formal way to say 'you' uses the exact same grammar as 'he' or 'she' (the third person). Because of this, seu is also used to mean 'your' when you are speaking to someone politely or formally.

Is there a more casual way to ask someone their name?