1340, from O.Fr.
ton (13c.), from L.
tonus "a sound, tone, accent," lit. "stretching" (in M.L., a term peculiar to music), from Gk.
tonos "vocal pitch, raising of voice, accent, key in music," originally "a stretching, taut string," related to
teinein "to stretch" (see
tenet). Sense of "manner of speaking" is from 1610. First reference to firmness of body is from 1669. The verb meaning "to impart tone to" is recorded from 1811.
Tonal is attested from 1776;
atonal first attested 1922;
tonality is from 1838.