Definition from Wiktionary, the free dictionary
Proper noun 
- A northern English and Scottish patronymic surname.
- Doctor Watson, fictional character in, and narrator of the Sherlock Holmes stories
- Any character who performs as catalyst for the protagonist detective's mental processes in a mystery story; a consciousness that's privy to facts in the case without being in on the conclusions drawn from them until the proper time. After William L. DeAndrea, discussing Sir Arthur Conan Doyle.
- James D. Watson co-discoverer of the structure of DNA