harmonic (adj.) Look up harmonic at Dictionary.com
1560s, "relating to music," from Latin harmonicus, from Greek harmonikos "harmonic, musical, skilled in music," from harmonia (see harmony). From 1660s as "tuneful, harmonious; relating to harmony" (earlier as armonical "tuneful, harmonious," c. 1500). The noun, short for harmionic tone, is recorded from 1777. Related: Harmonically.