means A higher frequency that sounds along with the fundamental pitch of a note, giving a voice or instrument its distinctive color — and, by extension, an implied meaning that hums beneath what's actually said.

from A transparent English compound of "over" plus "tone," coined in the 19th century as a translation of the German "Oberton" — itself a contraction of "oberer Ton," the "upper tone." The acoustician Hermann von Helmholtz popularized the concept in his studies of how tones layer above one another, and the figurative sense — meanings hovering above plain words — followed naturally from the music.