any of a family (Hippopotamyidae) of large, plant-eating, artiodactylous mammals with a heavy, thick-skinned, almost hairless body and short legs, that live chiefly in or near rivers; hippopotamus.

any of numerous saltwater or freshwater snakes; esp. any of a widely distributed genus (Natrix) of thick-bodied, non-poisonous, freshwater colubrine snakes that feed chiefly on fish and amphibians; water-snake.