D defs.my
Entry 1 sense Webster, 1913

Cachinnation

/(kăk`ĭn*nā"shŭn)/ · Cach·in·na·tion · IPA /kækɪˈneɪʃ(ə)n/
01 n. Loud or immoderate laughter; -- often a symptom of hysterical or maniacal affections.
  1. 1.
    Loud or immoderate laughter; -- often a symptom of hysterical or maniacal affections.
    “Hideous grimaces . . . attended this unusual cachinnation.” Sir W. Scott.