Origin of birthweight
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
In humans, the first weight of an infant, obtained within the first hour after birth. An infant of birth weight 512 pounds or more is considered full-sized.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.