overtone vs significance

overtone and significance both are nouns.

Word	Noun	Adjective	Verb	Adverb
overtone	Yes	No	No	No
significance	Yes	No	No	No

As nouns, significance is a hypernym of overtone; that is, significance is a word with a broader meaning than overtone:

Other hypernyms of overtone include import, meaning, signification.

overtone (noun)	significance (noun)
a harmonic with a frequency that is a multiple of the fundamental frequency	the quality of being significant
(usually plural) an ulterior implicit meaning or quality	a meaning that is not expressly stated but can be inferred
	the message that is intended or expressed or signified