The Collaborative International Dictionary of English v.0.48:

veterinarian \vet`er*i*na"ri*an\
   (v[e^]t`[~e]r*[i^]*n[=a]"r[i^]*an), n. [L. veterinarius. See
   Veterinary.]
   One skilled in the treatment of diseases of cattle or
   domestic animals; a veterinary surgeon. Often abbreviated to
   vet.
   [1913 Webster + PJC]

WordNet (r) 3.0 (2006):

vet
    n 1: a doctor who practices veterinary medicine [syn:
         veterinarian, veterinary, veterinary surgeon, vet]
    2: a person who has served in the armed forces [syn: veteran,
       vet, ex-serviceman]
    v 1: work as a veterinarian; "She vetted for the farms in the
         area for many years"
    2: examine carefully; "Someone should vet this report before it
       goes out"
    3: provide (a person) with medical care
    4: provide veterinary care for