cerebro
/θeˈɾebɾo/ · A2 · noun · m
brain
🧠 cerebro = cerebral: same Latin root, cerebrum (brain)
From Latin cerebrum, the source of English cerebral and cerebellum. In Spain the c is a soft th: theh-REH-bro. Calling someone un cerebro means they are the brains of the group, hence the nerd sense.