- the yellow and principal substance of an egg, as distinguished from the white.
- Embryology. the part of the contents of the egg of an animal that enters directly into the formation of the embryo, together with any material that nourishes the embryo during its formation.
- the essential part; the inner core.
- a natural grease exuded from the skin of sheep.
Origin of yolk
before 1000; Middle English yolke, yelke, Old English geoloca, derivative of geolu yellow
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- the substance in an animal ovum consisting of protein and fat that nourishes the developing embryoRelated adjective: vitelline
- a greasy substance secreted by the skin of a sheep and present in the fleece
Word Origin for yolk
Old English geoloca, from geolu yellow
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
Old English geolca, geoloca "yolk," literally "the yellow part," from geolu "yellow" (see yellow). Formerly also spelled yelk.
Online Etymology Dictionary, © 2010 Douglas Harper
- The portion of the egg of an animal that consists of protein and fat from which the early embryo gets its main nourishment and of protoplasmic substances from which the embryo develops.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- The yellow internal part of the egg of a bird or reptile. The yolk is surrounded by the albumen and supplies food to the developing young.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.