Sec"un*dine (?), n. [Cf. F.
secondine.] 1. (Bot.) 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.