Definition: quoted from WWWebster  http://www.m-w.com/cgi-bin/dictionary :
Main Entry: veg·e·tar·i·an·ism
Pronunciation: -E-&-"ni-z&m
Function: noun
Date: circa 1851
: the theory or practice of living on a diet made up of vegetables, fruits, grains, nuts, and sometimes eggs or dairy products

Definition: quoted from WWWebster  http://www.m-w.com/cgi-bin/dictionary :

Main Entry: veg·an
Pronunciation: 'vE-g&n also 'vA- also 've-j&n or- "jan
Function: noun
Etymology: by contraction from vegetarian
Date: 1944
: a strict vegetarian who consumes no animal food or dairy products; also : one who abstains from using animal products (as leather)

Definition: quoted from Britannica.com  http://www.britannica.com/bcom/eb/article/2/0,5716,118952+1+110237,00.html?kw=animal
animal (kingdom Animalia),
any of a group of multicellular eukaryotic organisms (i.e., as distinct from bacteria, their deoxyribonucleic acid, or DNA, is contained in a membrane-bound nucleus). They are thought to have evolved independently from the unicellular eukaryotes. Animals differ from members of the two other kingdoms of multicellular eukaryotes, the plants (Plantae) and the fungi (Mycota), in fundamental variations in morphology and physiology. This is largely because animals have developed muscles and hence mobility, a characteristic that has stimulated the further development of tissues and organ systems.

Definitions: quoted from the FAQ at The International Vegetarian Union site:

Vegan: excludes animal flesh (meat, poultry, fish and seafood), animal products (eggs and dairy), and usually excludes honey and the wearing and use of animal products (leather, silk, wool, lanolin, gelatin...). The major vegan societies all disallow honey, but some "vegans" still use it. Some "vegans " also refuse to eat yeast products. Dietary Vegan: follows a vegan diet, but doesn't necessarily try and exclude non-food uses of animals. Vegetarian: usually broken down further into OVO-LACTO, and LACTO. Vegetarians may or may not try and minimize their non food use of animals like vegans. Ovo-Lacto Vegetarian: same as VEGAN, but also eats eggs and milk products. This is the most 'popular' form of Vegetarianism. Lacto Vegetarian: Same as VEGAN, but also eats milk products. Veggie -- Shortened nick-name for a VEGETARIAN; often includes VEGANs. Strict vegetarian: originally meant vegan, now can mean vegan or vegetarian. The term 'Vegetarian' was coined in 1847. It was first formally used on September 30th of that year by Joseph Brotherton and others, at Northwood Villa in Kent, England. The occasion being the inaugural meeting of the Vegetarian Society of the United Kingdom. The word was derived from the Latin 'vegetus', meaning whole, sound, fresh, lively; (it should not be confused with 'vegetable-arian' - a mythical human whom some imagine subsisting entirely on vegetables but no nuts, fruits, grains etc.!) Prior to 1847, non-meat eaters were generally known as 'Pythagoreans' or adherents of the 'Pythagorean System', after the ancient Greek 'vegetarian' Pythagoras. The original definition of 'vegetarian' was "with or without eggs or dairy products" and that definition is still used by the Vegetarian Society today. However, most vegetarians in India exclude eggs from their diet as did those in the classical Mediterranean lands, such as Pythagoras. Definitions of some other confusing terms Semi-Vegetarian: Eats less meat than average person. See also PSEUDO VEGETARIAN. 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, carrots cannot). Vegetable Consumer: Means anyone who consumes vegetables. Not necessarily a VEGETARIAN. Herbivore: Mainly eats grass or plants. Not necessarily a VEGETARIAN. 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, bone meal and skin are not considered meat. Kosher: Made according to a complex set of Jewish dietary laws. Does not imply VEGAN in any case. Does not imply OVO-LACTO VEGETARIAN in any case. Even KOSHER products containing milk products may contain some types of animals which are not considered 'meat'. Pareve/Parve: One category in KOSHER dietary laws. Made without meat or milk products or their derivatives. Eggs and true fish are pareve, shellfish are not. Nondairy: Does not have enough percentage of milk fat to be called dairy. May actually contain milk or milk derivatives. Non meat: Made without meat. May include eggs, milk, cheese. Sometimes even included animal fats, seafood, fish, fowl.

Why Vegan? VEGANISM may be defined as a way of living which seeks to exclude, as far as possible and practical, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose. In dietary terms it refers to the practice of dispensing with *all* animal produce - including meat, fish, poultry, eggs, animal milks, honey, and their derivatives. Abhorrence of the cruel practices inherent in dairy, livestock and poultry farming is probably the single most common reason for the adoption of veganism, but many people are drawn to it for health, ecological, spiritual and other reasons. "Land, energy and water resources for livestock agriculture range anywhere from 10 to 1000 times greater than those necessary to produce an equivalent amount of plant foods. And livestock agriculture does not merely *use* these resources, it *depletes* them. This is a matter of historical record. Most of the world's soil, erosion, groundwater depletion, and deforestation -- factors now threatening the very basis of our food system -- are the result of this particularly destructive form of food production" (Keith Akers, p. 81, "A Vegetarian Source book", 1989). Words commonly used: Vegan: excludes animal flesh (meat, poultry, fish and seafood), animal products (eggs and dairy), and usually excludes honey and the wearing and use of animal products (leather, silk, wool, lanolin, gelatin...). The major vegan societies all disallow honey, but some "vegans" still use it. Strict vegetarian: originally meant vegan, now can mean vegan or vegetarian. Pure vegetarian: as per strict vegetarian. How is "vegan" Pronounced? The word was invented by Donald Watson in the 1940's. It is pronounced "vee-gun". This is the most common pronunciation in the UK today. No one can say this pronunciation in "wrong", so this is also the politically correct pronunciation. In the US, common pronunciations are "vee-jan" and "vay-gn" in addition to "vee-gn ", though the American Vegan Society says the correct pronunciation is as per the UK. The UK, and US and other places have other pronunciations. This is sometimes a touchy subject, so be prepared to change your pronunciation.... A little history Here are some of Donald's own words from the early years (1945): 'Vegetarian' and 'Fruitarian' are already associated with societies that allow the 'fruits' of cows and fowls, therefore.. we must make a new and appropriate word... I have used the title 'The Vegan News'. Should we adopt this, our diet will soon become known as the vegan diet and we should aspire to the rank of vegans.