Sec"un*dine (?), n. [Cf. F. secondine.]
The second coat, or integument, of an ovule, lying within the primine.
⇒ In the ripened seed the primine and secundine are usually united to form the testa, or outer seed coat. When they remain distinct the secundine becomes the mesosperm, as in the castor bean.
2. [Cf. F. secondines.]
The afterbirth, or placenta and membranes; -- generally used in the plural.
© Webster 1913.