this, from the WordDetective:
http://www.word-detective.com/041798.html
(way down toward the bottom)

"Perhaps the most surprising thing about "vet" is its origin, because it seems almost too simple. "Vet," the verb, like "vet" the noun, is a contraction of "veterinarian," and to "vet" originally meant to have your animal thoroughly examined by a vet. "Veterinarian," in turn, comes from the Latin "veterinae," or cattle, which constituted the bulk of early veterinarians' patients."


formerly known as etaoin...