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.

plural of yolk

Having a specified type of yolk.

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

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

plural of yolk sac

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.

plural of yolk plug

Of, pertaining to, or having the characteristics of yolk.