a calcareous prominence at the tip of the beak or upper jaw of an embryonic bird or reptile, used to break through the eggshell at hatching.
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Origin of egg tooth
First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for egg tooth
Traces of the egg-tooth were retained until the ninth day in two owls and until the 11th day in another.
In owl IV, the egg-tooth was lost sometime between the 9th and 14th day.
British Dictionary definitions for egg tooth
(in embryo birds and reptiles) a temporary tooth or (in birds) projection of the beak used for piercing the eggshell
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Science definitions for egg tooth
A hard, toothlike projection from the beak of embryonic birds, or from the upper jaw of embryonic reptiles, that is used to cut the egg membrane and shell upon hatching and that later falls off.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.