noun.
The practice of consuming a diet that does not include the flesh of animals and is mainly composed of plant parts (such as leaves, roots, fruits, nuts, and seeds), along with fungi, and sometimes eggs and dairy products.
The Century Dictionary and Cyclopedia
noun.
The theory and practice of living solely on vegetables.
the GNU version of the Collaborative International Dictionary of English
noun.
The theory or practice of living upon vegetables and fruits.