c.1200, "observe, take mental note of, mark carefully," from Old French noter "indicate, designate; take note of, write down," from Latin notare "to mark, to note, to make a note," from nota "mark, sign, note, character, letter" (see note (n.)). Meaning "to set in writing" is from early 14c. Related: Noted; noting.
c.1300, "a song, music, instrumental music; a musical note," from Latin nota "letter, character, note," originally "a mark, sign, means of recognition," which is perhaps related to notus, past participle of noscere (Old Latin *gnoscere) "to know" (see know). Meaning "notice, attention, reputation" is early 14c. Meaning "brief writing" is from 1540s.