We found 2 dictionaries that define the word first harmonics:

General (2 matching dictionaries)

1. first harmonics: Collins English Dictionary
2. first harmonics: Vocabulary.com

(Note: See first_harmonic as well.)

Definitions from WordNet (first harmonic) ▸ noun:  the lowest tone of a harmonic series ▸ Also see first_harmonic ▸ Words similar to first harmonics ▸ Usage examples for first harmonics ▸ Idioms related to first harmonics ▸ Wikipedia articles (New!) ▸ Words that often appear near first harmonics ▸ Rhymes of first harmonics ▸ Invented words related to first harmonics