Learn Spanish (Latin America): Mi tercer hermano vive en el cuarto o quinto piso. - My third brother lives on the fourth or fifth floor.

Mi tercer hermano vive en el cuarto o quinto piso.

My third brother lives on the fourth or fifth floor.

Breakdown of Mi tercer hermano vive en el cuarto o quinto piso.

el hermano

the brother

vivir

to live / to be constantly (doing something)

in / on / at

Questions & Answers about Mi tercer hermano vive en el cuarto o quinto piso.

Why is it tercer and not tercero?

The word for "third" is tercero. However, when it comes directly before a masculine singular noun like hermano (brother), it drops the final "o" and becomes tercer. The same thing happens with primero (first), which becomes primer.

Since it is tercer hermano, why do cuarto and quinto keep their "o" before piso?

Only primero (first) and tercero (third) drop their final "o" before masculine singular nouns. The other ordinal numbers, like cuarto (fourth) and quinto (fifth), do not have this rule and always keep their full form.

Doesn't en mean "in"? Why is it used here for living "on" a floor?

In Spanish, the preposition en is very flexible and can mean "in", "on", or "at" depending on the context. When talking about being on a certain floor of a building, you always use en.

Wait, doesn't the word cuarto mean "room"?

Yes, it does! Cuarto can be the ordinal number "fourth" (as it is here with cuarto piso - fourth floor) or it can be a noun meaning "room" (like a bedroom). You can easily tell which one is meant based on the context of the sentence.