Egg yolk is the inner portion of the egg and is a good source of protein, iron, vitamins A and D. Egg yolks are also high in cholesterol (about 213 milligrams per egg).(Definition by cooking.com)
nutritive material of an ovum, consisting of protein and fat, stored for the nutrition of an embryo or early larva
nutritive material of an ovum stored for the nutrition of an embryo (especially the yellow mass of a bird or reptile egg)
The intracellular food reserve of a fertilized egg. In birds, the yolk is yellow and becomes surrounded by the white.
The food store in the eggs of the majority of animals, made up mainly of fat and protein granules. Where yolk is present in the egg, as in chickens, there is meroblastic cleavage, but where it is absent, or nearly so, cleavage is holoblastic, as in Amphioxus.
The yellow portion of the egg composed of water, protein, and glyceride. The yolk contains practically all of the known vitamins except vitamin C.
ME yolke - the yolk, the yellow part]. Nutritive stores found within the ovum cytoplasm consisting of proteins and fats.