A musicologist is a person who studies music as history and careful thinking, not mainly a person who gets on stage and plays. The work is the study of music, especially how different kinds of music grew in different times and places — who wrote it, how it was passed on, what it meant to people. A pianist plays; a musicologist may spend years with old papers, recordings, and instruments. The word is formal. You meet it in universities, museums, and serious programme notes, not in everyday chat about a favourite band. Though actually, some musicologists play very well; the title still points to the studying.