Welcome to the The Incredible Edible Egg™ Eggcyclopedia, where you can access the latest egg information from A-Z. The Eggcyclopedia was developed by the American Egg Board (AEB) on behalf of America's egg farmers who are committed to caring for their hens and producing high-quality eggs for you and your families.

Just click on any letter below to bring up a list of egg terms and their related definitions.


A quality-control measure to supplement the grading process. The following criteria have been set by the U.S. Department of Agriculture (USDA) to judge egg quality:  Sample eggs are selected at random and broken out onto a level surface; The height of the thick albumen (white) is measured with a tripod micrometer and this measurement is correlated with the weight of the egg to give a Haugh unit measurement - a high Haugh value means high egg quality; At the same time, the condition of the yolk is observed.

The foodservice industry also uses a breakout test to evaluate the quality of eggs purchased. Simple observations of the condition of albumen (white) and yolk are considered adequate; generally the Haugh unit system is not used.

– See Grading, Haugh Unit

Grade AA


Egg content covers a small area.  White is firm, has much thick white surrounding the yolk and a small amount of thin white.  The yolk is round and upstanding.

Grade A


Egg content covers a moderate area. White is reasonably firm and has a considerable amount of thick white and a medium amount of thin white. The yolk is round and upstanding.

Grade B


Egg content covers a very wide area. White is weak and watery, has no thick white and the large amount of thin white is thinly spread. The yolk is enlarged and flattened.