A person who does not eat meat, including birds and fish. Many times vegetarians believe that killing animals today for food is immoral and unnecessary because we are able to survive off of other foods. A person who doesn't eat any meat except for fish is a pescatarian. A person who doesn't eat any meat or other animal products such as eggs, milk, and cheese is a vegan.
There are meat eaters, pescatarians, vegetarians, vegans, and raw foodists (which becomes obsessive compulsive in my opinion).