海豚音

hǎitúnyīn
(singing) (coll.) whistle note

CEDICT

colloquial

Entry Composition

1 海豚 hǎitún dolphin
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)