In English, there are different terms for animals and their meat. For example, a cow is still a cow when it’s alive but when it’s been killed and is ready to eat, we call it ‘beef’. The same happens in the case of man other animals:
ANIMAL (Germanic word) MEAT (French origin word)
pig / swine pork
ox / cow beef (from Old French boeuf)
The reason for this comes from the Middle Ages when most of England was ruled by French-speaking lords and noblemen.
The peasants working in the fields spoke Old English but the lords in their castles and their chefs spoke French. So, in the field, an animal had an English name but once it got to the kitchen, the French name was used.
With the passage of time, both words became part of English but with slightly different meanings: either the live animal and the meat.
For an extended list of pairs of French and Anglo-Saxon origin pairs in English check the list in Wikipedia.