If the name tadpole for the early stage of frog or toad had gone along with other changes in our language through the centuries, no explanation of its source would be needed.
Tad is merely a survival of the way toad was spelled and pronounced four hundred years ago, and pole was a seventeenth-century substitution for poll, “head.”
The name toadhead for the larva in the stage when it consists of little more than a round head with a tail is simple.
