Wat ‧ son, Dr /ˈwɒts ə n $ ˈwɑː-/ BrE AmE
one of the main characters in Sir Arthur Conan Doyle’s stories about Sherlock Holmes. Watson is Holmes’s friend and helps him in his work, but he is much less intelligent than Holmes. Most people know the expression ‘Elementary, my dear Watson’, which Holmes is supposed to say to Watson when he is explaining how easy it is to understand something about a crime, which Watson has not noticed or does not understand. People sometimes use this expression humorously to say how easy something is to solve.