I was just watching QI, and one of the questions was about the origin of the word 'vegetarian' and apparently according to the Vegetarian Society it has nothing to do with vegetation, but is derived from the latin word 'vegetus' which means lively, fresh, and vigorous.
Nice little fact to keep in mind! (:
Urban dictionary's definition of Vegan:
Someone who slaughters and kills fruits, and vegetables.
People on the internet love making fun of vegans (and vegetarians) labeling us all as PETA (people eating tasty animals) extremists who are all hypocrities because plants have feelings too.