'Proembryo' definitions:

Definition of 'Proembryo'

From: GCIDE

Proembryo \Pro*em"bry*o\, n. [Pref. pro- + embryo. ] (Bot.) (a) The series of cells formed in the ovule of a flowering plant after fertilization, but before the formation of the embryo. (b) The primary growth from the spore in certain cryptogamous plants; as, the proembryo, or protonema, of mosses. [1913 Webster]