Definition from Wiktionary, the free dictionary
- A northern English and Scottish patronymic surname.
- Any character who acts as a catalyst for the detective protagonist's mental processes in a mystery story; a consciousness that is 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.
- Doctor Watson, fictional character in, and narrator of the Sherlock Holmes stories.
- James D. Watson, co-discoverer of the structure of DNA.