egg

An egg is the reproductive body produced by female birds, most commonly the domesticated chicken (Gallus gallus domesticus), consisting of a protein-rich white (albumen), a nutrient-dense yellow yolk, and a hard calcium carbonate shell. The chicken egg is the most widely consumed egg globally, though duck, quail, goose, and emu eggs are also used culinarily. The shell color varies from white to brown depending on breed, with no nutritional difference. Internally, the thick albumen provides structure when cooked, while the yolk contributes richness, emulsifying properties, and a range of flavors from mild to distinctly eggy depending on the hen's diet and freshness.

Eggs are classified by size (peewee through jumbo) and grade (AA, A, B in the United States), with grade determined by the condition of the albumen, yolk, and shell integrity. Nutritionally complete, eggs contain all nine essential amino acids and are one of the few natural sources of choline.

Eggs are among the most versatile ingredients in world cuisine, functioning as binder, leavening agent, emulsifier, thickener, and primary protein in countless preparations. They are consumed cooked in numerous styles—fried, scrambled, poached, boiled, baked—and form the base of custards, mayonnaise, hollandaise, meringues, and cake batters. In Asian cuisines, eggs appear in fried rice, noodle dishes, and preserved forms like century eggs and salted duck eggs. They are essential to French cuisine (omelets, quiches, soufflés) and Italian pasta dough. Scrambled or cooked eggs pair with virtually any savory ingredient; conversely, raw or lightly cooked yolks emulsify vinaigrettes and sauces. Temperature control is critical—gentle heat produces creamy results, while high heat yields firm textures.