a very long, heavy South American boa (Eunectes murinus) that lives in trees and water
See anaconda in American Heritage Dictionary 4
(ănˌə-kŏnˈdə)
noun
Either of two nonvenomous, semiaquatic snakes (Eunectes murinus or E. noteus) of tropical South America that kill their prey by suffocating it in their coils. E. murinus, the giant anaconda, can attain lengths from 5 to 9 meters (16.4 to 29.5 feet).