A person born in Rio de Janeiro. This is a special Portuguese word.
Carioca is a concept that involves other cultural aspects besides birth place. The Carioca is known to be beautiful, happy and sexy. The reasons behind this might be worth a thesis, but I risk to say that it is well know that most Cariocas loves beaches.
There are many songs on the subject, but "Cariocas" by Adriana Calcanhotto reflects the idea very well.
Another interesting cultural aspect of Cariocas is the accent: very different from other Brazilian places and usually instantly recognized.