a large black gibbon, Hylobates (or Symphalangus) syndactylus, of Sumatra and the Malay Peninsula, having a large reddish-brown vocal sac beneath the chin and the second and third toes united
Word origin
C19: from Malay
siamang in American English
(ˈsiəˌmæŋ)
noun
a very agile black gibbon (Symphalangus syndactylus) of the Malay Peninsula and Sumatra