vitellus

The yolk of an egg.

The yolk of an egg; in the broadest sense, the protoplasm of an ovum; the germinative or formative protoplasmic contents of an ovum-cell, which is transformed into the body of the embryo, plus that substance, if any, which nourishes the embryo during its germination and subsequent growth.

The contents or substance of the ovum; egg yolk. See Illust. of Ovum.

Perisperm in an early condition.

The contents or substance of the ovum; egg yolk.

Perisperm in an early condition.

nutritive material of an ovum stored for the nutrition of an embryo (especially the yellow mass of a bird or reptile egg)