

vegetable (adj.) c.1400, "living and growing as a plant," from O.Fr. Also the word Vegetable (from which the word vegetarian is derived) has latin origins ( not native american ) so either your local sioux holidayed in rome or was descended from roman stock is at best very improbable. The OED writes that the word came into general use after the formation of the Vegetarian Society at Ramsgate in 1847, though it offers two examples of usage from 18. Despite this, the Oxford English Dictionary (OED) and other standard dictionaries state that the word was formed from the term "vegetable" and the suffix "-arian". The Vegetarian Society, founded in 1847, says that the word “vegetarian” is derived from the Latin word vegetus meaning lively or vigorous.

"The general use of the word appears to have been largely due to the formation of the Vegetarian Society in Ramsgate in 1847". ie (from the etymology dictionary available online) - irregular formation from vegetable (n.) + -arian, as in agrarian, etc. Hate to disillusion you, but as an etymologist ( basically somebody who studies words and their origins) but the word vegEtarian is generally acknowledged as being formed and coming into use in 1839.
