基音

jīyīn
fundamental tone

CEDICT

  1. (music) fundamental tone; fundamental frequency
  2. fundamental tone; fundamental frequency

Wiktionary

发音体振动产生複合音时，其中频率最低的音，即为构成主要振动的音，称为「基音」。

重編國語辭典

Entry Composition

1 基 jī
  1. (bound form) base; foundation
  2. (bound form) radical (chemistry)
  3. (bound form) gay (loanword from English into Cantonese, Jyutping: gei1, followed by orthographic borrowing from Cantonese)
2 音 yīn
  1. sound
  2. noise
  3. note (of musical scale)
  4. tone
  5. news
  6. syllable
  7. reading (phonetic value of a character)