The young aquatic larva of any amphibian. In this stage it breathes by means of external or internal gills, is at first destitute of legs, and has a finlike tail. Called also polliwig, polliwog, porwiggle, or purwiggy.
- The limbless aquatic larva of a frog or toad, having gills and a long flat tail. As the tadpole approaches the adult stage, legs and lungs develop, and the tail gradually disappears. Also called polliwog.