2. (noun) From the words overt & ringtone. The assignment of a ringtone to imply something about a caller. Usually used as a a friendly jab or an insult. For instance, overtoning Sir Mix-a-lot's "Baby Got Back" as the ringtone for a chubby friend is an overtone.
Alice: Bob, who was that who just called you?
Alice: OMG! That's why your phone played "Macho Man!" Nice overtone.
Bob: Yeah, Chuck's totally closeted.