harmonic

Concise Oxford English Dictionary © 2008 Oxford University Press:
harmonic /hɑːˈmɒnɪk/

▶adjective

• 1 relating to or characterized by harmony: a four-chord harmonic sequence.

• 2 Music relating to or denoting a harmonic or harmonics.

• 3 Mathematics relating to a harmonic progression.

  ■ Physics of or denoting components of a complex oscillation or wave whose frequencies are exact multiples of the basic frequency.

• 4 Astrology relating to a division of the zodiacal circle by a whole number.

▶noun

• 1 Music an overtone accompanying a fundamental tone at a fixed interval, produced by vibration of a string, column of air, etc. in an exact fraction of its length.

  ■ a note produced on a musical instrument as an overtone, e.g. by lightly touching a string while sounding it.

• 2 Physics a harmonic component of a complex oscillation or wave.

– derivatives
harmonically adverb.