This article is from the Vegetarianism FAQ, by firstname.lastname@example.org (Michael Traub) with numerous contributions by others.
Semi-Vegetarian: Eats less meat than average person. See also
Pseudo-Vegetarian: Claims to be vegetarian, but isn't.
Often used by VEGETARIANS to describe
SEMI-VEGETARIANs, and PESCETARIANs.
Pescetarian: Same as VEGETARIAN, but also consumes fish.
(often is a person avoiding factory-farming
techniques...) See also PSEUDO-VEGETARIAN.
Fruitarian: Same as VEGAN, but only eats foods that don't kill the
plant (apples can be picked without killing plant,
Vegetable Consumer: Means anyone who consumes vegetables. Not
necessarily a VEGETARIAN.
Herbivore: Mainly eats grass or plants. Not necessarily a
Plant-Eater: Mainly eats plants. Not necessarily a VEGETARIAN.
Nonmeat-Eater: Does not eat meat. Most definitions do not consider
fish, fowl or seafood to be meat. Animal fats and
oils, bonemeal and skin are not considered meat.