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.


Garlic mayonnaise popular in the Provence region of southern France.

– See Mayonnaise

Air Cell

The air-filled pocket between the white and shell at the large end of the egg.

When an egg is newly laid, it is about 105ºF (41ºC) and has either no air cell or a very small one. As the egg cools, the liquid contents contract more than the shell and the inner shell membrane separates from the outer shell membrane to form the air cell. As the egg ages, moisture and carbon dioxide leave through the pores of the shell, air enters to replace them and the air cell becomes larger. The flattened end of a peeled, hard-boiled egg shows you where the air cell once was.

The formation of the air cell and the separation of the shell membranes are the reason that a slightly older egg is easier to peel after hard-boiling. Storing eggs upright in their cartons in the refrigerator helps to keep their air cells in place and maintain egg quality.

Although the air cell usually forms in the large end of the egg, it occasionally moves freely toward the uppermost point of the egg as the egg is rotated. It is then called a free or floating air cell. If the main air cell ruptures, resulting in one or more small separate air bubbles floating beneath the main air cell, it is known as a bubbly air cell.

Candlers use the size of the air cell as one basis for determining grade.

– See Candling, Composition, Grading, Peeling


Also known as egg white. Depending on the size of the egg, albumen accounts for most of an egg’s liquid weight, about 66%. The white contains more than half the egg’s total protein, a majority of the egg’s niacin, riboflavin, magnesium, potassium and sodium, and none of the fat. The white of a large egg contains about 17 calories.

Albumen color is opalescent and doesn’t appear white until an egg is beaten or cooked. The cloudy appearance comes from carbon dioxide. As eggs age, carbon dioxide escapes, so the albumen of older eggs is more transparent than that of fresher eggs.

The albumen consists of four alternating layers of thick and thin consistencies. From the yolk outward, they are designated as the inner thick or chalaziferous white, the inner thin white, the outer thick white and the outer thin white. As an egg ages, the egg white tends to thin out because its protein changes in character. That’s why fresh eggs sit up tall and firm in the pan while older ones tend to spread out.

When you beat egg white vigorously, it foams and increases in volume six to eight times. Egg foams are essential for making meringues, puffy omelets, soufflés, angel food and sponge cakes.

– See BreakoutChalazae, Color, White, Composition, Cooking Functions, Cooking Terms, Foam, Formation, Grading, Nutrient

American Egg Board

American Egg Board (AEB) is the promotion (advertising, marketing communications), education and research organization for the U.S. egg industry. The Board is composed of 18 members and 18 alternates. All members are egg producers who have been appointed by the Secretary of Agriculture to administer the program on behalf of all egg producers in the 48 contiguous states.

The Board was authorized by the Egg Research and Consumer Information Act passed by the 93rd Congress. The purpose of the law is “to enable egg producers to establish, finance and carry out a coordinated program of research, producer and consumer education and promotion to improve, maintain and develop markets for eggs and egg products.” The activities of AEB are conducted under the oversight of the U.S. Department of Agriculture (USDA).

The staff of AEB implements the programs and policies of the Board. Major programs consist of a national advertising and public relations campaign, as well as egg product, foodservice and retail marketing outreach and nutrition education activities, which are conducted through the AEB-funded Egg Nutrition Center.

Angel Food Cake

A cake, tall and light in texture, leavened only by beaten egg whites.

Click here for an Angel Food Cake recipe.

Avian Influenza

Avian influenza (AI), also referred to as bird flu, is a virus that infects all types of avian species, including wild birds and domestic poultry. AI is an animal health issue that causes mild to severe symptoms in birds and, in its most extreme form, can be fatal to infected birds.

The U.S. egg industry has had years of experience dealing with AI in commercial poultry flocks. Egg farmers work closely with the U.S. Department of Agriculture (USDA) in these efforts and are well-equipped to identify AI outbreaks quickly and erradicate them immediately.

Humans cannot get AI through eating thoroughly cooked eggs as proper cooking easily destroys all AI virus particles. The U.S. Department of Agriculture, the Food and Drug Administration and the World Health Organization all agree that properly cooked eggs are safe to eat. Cook basic egg recipes until the yolk and white are firm and cook or bake any dishes containing eggs until they reach 160o F.

For more details about Avian Influenza, visit

– See Cooking Methods, Doneness Guidelines, Egg Safety, Partnership for Food Safety Education, Raw Eggs


A protein found in small amounts (about 0.05%, five one-hundredths of 1%) in egg albumen. Avidin is inactivated by heat.

– See Biotin