I. här-ˈmä-nik adjective
Date: 1570
1. : musical
2. : of or relating to musical harmony or a harmonic
3. : pleasing to the ear : harmonious
4. : of an integrated nature : congruous
• har·mon·i·cal·ly -ni-k(ə-)lē adverb
II. noun
Date: 1777
1.
a. : overtone ; especially : one whose vibration frequency is an integral multiple of that of the fundamental
b. : a flutelike tone produced on a stringed instrument by touching a vibrating string at a nodal point
2. : a component frequency of a complex wave (as of electromagnetic energy) that is an integral multiple of the fundamental frequency