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When you stop and think about it, it’s actually quite strange that pig
meat is called “pork,” cow meat is called “beef,” sheep meat is called
“mutton,” and deer meat is called “venison.” What’s even stranger is
that chicken meat is still called “chicken,” and fish is “fish.” So what
gives?
The answer actually involves a rather complicated lesson in etymology,
but we’ll try to put it as simply as possible.
According to eGullet, it all goes back to the Norman conquest of Britain
in 1066. When the French took over England, there became two ways of
saying a whole lot of words, and from a gastronomic standpoint the
French won out (as they usually do). This is likely because the
lower-class Anglo-Saxons were the hunters (so we get the animal names
from them), and the upper-class French only saw these animals on the
dinner table (so we get the culinary terms from them).
So the Anglo-Saxon pig became the French porc, which was Anglicized to
pork; the Anglo-Saxon cow became the French boeuf, which became beef;
and sheep became mouton, (later mutton). Even chicken got a new culinary
name: pullet, which is the Anglicized version of the French poulet, and
is now only used to refer to a young hen. All of those French terms are
still the French words for those animals (as well as their meat) today.
As for fish, we most likely still call it fish because the French term
for it, poisson, is too close to the English word poison.
The reason behind calling deer meat “venison” is slightly more
complicated, but still has to do with the Norman Invasion (deer in
French is cerf, which doesn’t sound much like “venison”). According to
Yahoo, the word venison derives from the Latin word venor, meaning “to
hunt or pursue.” Following the invasion and the establishment of the
Royal Forests, any hunted animal was called “venison” after it was
killed; because more deer were hunted than any other animal, the name stuck.
The Norman invasion’s effect on the English language really can’t be
understated. Other words that now have two ways of saying them thanks to
French influence include the Anglo-Saxon want to the Norman desire, ask
to inquire, and hide to obscure.