/ Dictionary / Index H harmonic series: Meaning and Definition of Find definitions for: harmon'ic se'ries Pronunciation: [key] — Math. Math. a series in which the reciprocals of the terms form an arithmetic progression. the divergent infinite series, 1 + + + + +. … Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. harmonics harmonic tone Related Content Daily Word Quiz: vertigo Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language