mid-13c., musike, "a pleasing succession of sounds or combinations of sounds; the science of combining sounds in rhythmic, melodic, and (later) harmonic order," from Old French musique (12c.) and directly from Latin musica "the art of music," also including poetry (also source of Spanish musica, Italian musica, Old High German mosica, German Musik, Dutch muziek, Danish musik), from Greek mousikē (technē) "(art) of the Muses," from fem. of mousikos "pertaining to the Muses; musical; educated," from Mousa "Muse" (see muse (n.)). Modern spelling from 1630s. In classical Greece, any art in which the Muses presided, but especially music and lyric poetry.
The use of letters to denote music pitch probably is at least as old as ancient Greece, as their numbering system was ill-suited to the job. Natural scales begin at C (not A) because in ancient times the minor mode was more often used than the major one, and the natural minor scale begins at A.
Meaning "the written or printed score of a composition" is from 1650s. Music box is from 1773, originally "barrel organ," by 1845 in reference to the wind-up mechanical device; music hall is by 1842 as "interior space used for musical performances," especially "public hall licensed for musical entertainment" (1857). To face the music "accept the consequences" is from 1850; the exact image is uncertain, one theory ties it to stage performers, another to cavalry horses having to be taught to stay calm while the regimental band plays. To make (beautiful) music with someone "have sexual intercourse" is from 1967.