It is the name of a genus of anacondas or güios that are large aquatic and non-venomous constrictor snakes. They belong to the family Boidae. The word eunectes, is formed of two roots: the Latin root eu which means good, skillful and the Greek root nectes which means to swim, to move in the water: that is, that eunectes means, good to swim, skillful to move in the water.