any of a genus (Dendroaspis) of extremely poisonous, elapine, African tree snakes similar to the cobras but not hooded; esp., a long, green E African snake (D. angusticeps)
See mamba in American Heritage Dictionary 4
(mämˈbə)
noun
Any of several venomous arboreal snakes of the genus Dendroaspis of tropical Africa, especially D. angusticeps, a green or black tree snake having an often fatal bite.