Botany. The endosperm of a seed, esp. when occurring as a persistent storage tissue in the mature seed. Cf. albuminous, adj. 2.

Botany. The perisperm of a seed, esp. as a source of nourishment for the developing embryo. Cf. vitellus, n. 2a. Obsolete.

In some seeds: a layer of nutritive tissue derived from the nucellus and located outside the embryo sac. Formerly also: †the testa or endosperm of a…

Botany. A fleshy sac situated between the albumen and the embryo in a seed.

A related substance found in the seeds of plants. Also attributive.

any of various polypeptides occurring in plants that are the products of partial proteolysis.

albumin occurring in plants.