Why does “carteira” mean wallet and school desk in Portuguese?

Carteira looks like several unrelated words at once. It is your wallet, the desk a pupil sits at, and the card that proves who you are — carteira de identidade, carteira de motorista. One root ties them together: carta, from Latin charta, “sheet of paper.” A carteira is whatever holds or handles paper, so the wallet, the writing desk and the ID booklet turn out to be the same idea.

The heaviest one in Brazil is the carteira de trabalho, the work booklet created in 1932 that records every formal job, its salary and its dates. Trabalhar de carteira assinada — “with a signed carteira” — is the everyday shorthand for having a proper contract with full legal rights, and it is what people mean when they contrast formal with informal work. Finance borrowed the word too: a carteira de clientes or carteira de investimentos is a portfolio. The driving licence is officially the CNH, but in speech it is usually just the carteira.