Why are pigs pork?

Pork is the name for the meat of the animal we call a pig, see: cow = beef, deer = venison. There is no "reason" for this it's just the way English does it. Other languages are far more straight forward, Hungarian for example, just adds the word 'hús' which means 'meat', so disznőhús = pig meat, csirkéhús = chicken meat, etc.