The yellow, spherical part of an egg that is surrounded by the white albumen, and serves as nutriment for the growing young. / The grease in a sheep's fleece; lanolin.

Having a specified type of yolk.

plural of yolk

plural of egg yolk

(anatomy) A membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals.

The yellow central part of a chicken’s (or other bird’s) egg.

The large edible endothermal cells surrounded by the blastopore of an amphibian gastrula during its later stages

plural of yolk sac

plural of yolk plug

(in combination) An egg with the specified number of yolks.