yolk

The portion of the egg of egg-laying vertebrates, such as reptiles and birds, and of certain invertebrates that consists chiefly of protein and fat and serves as the primary source of nourishment for the early embryo.

This portion of the egg of a bird, especially a chicken, which is large, yellow, and surrounded by albumen.

A greasy substance found in unprocessed sheep’s wool, which is refined to make lanolin.

See yoke.

The yellow and principal substance of an egg, as distinguished from the white; that protoplasmic content of the ovum of any animal which forms the embryo in germination, with or without some additional substance which serves to nourish the embryo during its formation, as distinguished from a mass of albumen which may surround it, and from the egg-pod or shell which incloses the whole; the vitellus, whether formative wholly or in part.

The vitellus, a part of the seed of plants, so named from its supposed analogy with the yolk of an egg.

The greasy sebaceous secretion or unctuous substance from the skin of the sheep, which renders the fleece soft and pliable; wool-oil.

The yellow part of an egg; the vitellus.

An oily secretion which naturally covers the wool of sheep.