The aquatic larva of a frog or toad, having gills, a long, laterally compressed tail, and in early stages, no limbs. During metamorphosis of a tadpole into an adult, legs and lungs develop, and the tail gradually disappears. Also called polliwog.
Word History: The word tadpole, which first appears in English in the 1400s, is an old compound word whose meaning is no longer transparent. Tad is a variant of the word toad, while pole is simply an alternative spelling of poll, meaning "head." Tadpole thus means "a toad that is all head," so to speak. Nowadays, the original meaning of the word poll, "head," is most prominent in poll tax, "a tax consisting of a fixed amount and levied on all individuals," a kind of tax that also often used to be called a head tax. (In modern times, poll taxes are most often levied on adults eligible to vote.) The most common senses of poll today are probably "a survey of public opinion" and "the place where votes are cast." The word probably developed these senses at least partly through the notion of the head as the most prominent part of each individual in a crowd—the part that could be counted. A similar notion is found in the phrase "a head of cattle."
(click for a larger image)tadpole
from top to bottom:
egg and three stages of a tadpole metamorphosing into a frog
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.