notation n.

c. 1200, noten, "observe, take mental note of, mark carefully," from Old French noter "indicate, designate; take note of, write down," from Latin notare "to mark, note, make a note," from nota "mark, sign, note, character, letter" (see note (n.)). Sense of "mention separately or specially among others" is from late 14c. Meaning "to set down in writing, make a memorandum of" is from early 14c. Related: Noted; noting.

"set down in musical notation," 1871, a back-formation from notation, or else from Latin notatus, past participle of notare "to mark, note, make a note," from nota "mark, sign, means of recognition" (see note (n.)). Related: Notated; notating.