A vegan is a person who practices and endorses the concept of veganism.
Veganism is a philosophy and way of living which seeks to exclude—as far as is possible and practicable—all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose; and by extension, promotes the development and use of animal-free alternatives for the benefit of animals, humans and the environment. In dietary terms it denotes the practice of dispensing with all products derived wholly or partly from animals.
Definition sourced from: The Vegan Society.
Vegans avoid:
Eating animal-derived products (meat, dairy, eggs, honey, etc.)
Using products tested on animals (cosmetics, cleaning supplies, etc.)
Wearing clothing made from animal products (leather, wool, silk, etc.)
Supporting animal exploitation for entertainment purposes (zoos, aquariums, circuses, etc.)
Participating in activities that exploit animals for sport (hunting, fishing, horse racing, etc.)
Using animals for medical research or experimentation
Keeping animals as pets for human pleasure or convenience (except in cases where the animal has been rescued or needs assistance)