A cat, or an informal/affectionate name for a person (usually a young woman).
From Dutch 'pus' or Low German origin, possibly imitating the sound a cat makes. By the 1600s, it became affectionate slang for a person, and 'puss in boots' (the fairy tale) made it famous.
The word 'puss' might come from trying to call a cat—people across many languages independently made 'pss' or 'poos' sounds, and the Dutch/German word got adopted into English because it actually worked to get cats' attention!
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