This is the 97th most frequent French word.
pouvoir
"Pouvoir" means "to be able to" or "can."
The word 'peux', a conjugation of 'pouvoir' in the first person singular, indicates the ability to perform an action.
Je peux jouer du piano.
I can play the piano.
The inverted structure 'Puis-je' is a formal question form using 'pouvoir', indicating polite permission or ability.
Puis-je vous aider?
May I help you?
The past tense conjugation 'pu' of 'pouvoir' illustrates an inability to complete an action in the past.