late 14c., "one of the nine Muses of classical mythology," daughters of Zeus and Mnemosyne, protectors of the arts; from Old French Muse and directly from Latin Musa, from Greek Mousa, "the Muse," also "music, song," ultimately from PIE root *men- (1) "to think." Meaning "inspiring goddess of a particular poet" (with a lower-case m-) is from late 14c.
The traditional names and specialties of the nine Muses are: Calliope (epic poetry), Clio (history), Erato (love poetry, lyric art), Euterpe (music, especially flute), Melpomene (tragedy), Polymnia (hymns), Terpsichore (dance), Thalia (comedy), Urania (astronomy).