vet (n.1) Look up vet at
1862, shortened form of veterinarian.
vet (n.2) Look up vet at
1848, shortened form of veteran (n.).
vet (v.) Look up vet at
"to submit (an animal) to veterinary care," 1891, from veterinarian. The colloquial sense of "subject (something) to careful examination" (as of an animal by a veterinarian, especially of a horse before a race) is attested by 1901. Related: Vetted; vetting.