noun (formerly also porˈpess, porˈpesse or (Spenser) porcˈpisce)
A short-snouted genus (Phocaena) of cetaceans related to the dolphin family, 1.2 to 2.5 metres (4 to 8 feet) long, gregarious in habits, yielding an oil and leather
Extended to similar forms, esp (loosely) the dolphin
intransitive verb
To move like a porpoise
ORIGIN: OFr porpeis, from L porcus a pig, and piscis a fish