DOC is an abbreviation for "doctor," which is a title typically used to refer to medical professionals. However, based on the clue "Vet, e.g.," in this context, DOC most likely stands for "doctor of veterinary medicine," referring to a veterinarian.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Vet, e.g.. Explanations are generated by AI and may be inaccurate.