The English term vegan (pronounced vígan) was created in 1944 at a meeting organized by Donald Watson (1910 - 2005) involving 6 people (after disaffiliating from The Vegetarian Society due to ideological differences), where it was decided to create a new society (The Vegan Society) and adopt a new term to define themselves.
This is a corruption of the word "vegetarian", where the first 3 letters and the last 2 are considered to form the word vegan.
In Portuguese the first three and the last three letters (vegetariano) are considered to form the term vegano (s.m. adepto do veganismo - fem.vegana).
Donald Watson defined veganism as a lifestyle that seeks to exclude, as far as possible and practicable, all forms of exploitation of and cruelty to animals, for food, clothing, and any other purpose.
Veganism means the principles by which human beings live without exploiting animals. It is the practice and pursuit of ending the use of animals for food, appropriation, labor, hunting, vivisection, confinement, and all other uses that involve exploitation of animal life. Vegans seek to abolish any practice that exploits animals, ensuring the preservation of animal freedom and integrity. They also boycott any animal products (food or otherwise), as well as products that have been tested on animals or include any possible form of animal exploitation in their ingredients or manufacturing processes. In other words, they do not use any beauty, personal care, cleaning products, etc. that are not cruelty-free.
They prefer to use the terms "non-human animals" or "sentient beings" rather than "irrational".
It is very important to differentiate vegan ideology from vegetarian diet. Veganism is not a diet. It is a set of practices focused on Animal Rights that consequently adopts a strictly vegetarian diet. It is understood that animals have the right not to be used as property, and veganism is the ethical basis for taking that right seriously, for the minimum respect of them.