Lacto-Ovo-Vegetarians (vegetarianism in its most common form in Western societies) eat eggs and dairy products.
Lacto-Vegetarians are common throughout India in particular. They eat dairy products, but refuse eggs.
Ovo-Vegetarians accept eggs but refuse dairy products. This is a relatively uncommon form of vegetarian.
Other groups include individuals who refuse all red meat, but eat poultry and fish/seafood, and individuals who refuse meat and poultry but eat fish/seafood. Neither group can rightfully be labelled Vegetarian, and must be categorized as a subset of the omnivorous diet.