What is a baby frog called before it grows legs?

A baby frog is called a tadpole before it grows legs. A tadpole hatches from an egg looking almost like a tiny fish, swimming with a long tail and breathing through gills underwater, completely unlike the hopping, land-and-water frog it will eventually become.

A chick is a baby bird and a puppy is a baby dog, both born looking like small versions of their parents, unlike a tadpole, which starts life looking nothing like an adult frog at all.

As a tadpole grows, it goes through metamorphosis, sprouting back legs first, then front legs, shrinking its tail, and developing lungs, eventually leaving the tail behind entirely so it can hop and breathe air on land.