n. [ Pref. deuto- + Gr. &unr_; form. ] (Biol.) The lifeless food matter in the cytoplasm of an ovum or a cell, as distinguished from the active or true protoplasm; yolk substance; yolk. [ 1913 Webster ]
n. [ Ecto- + Gr. &unr_; form. ] (Biol.) (a) The outer transparent layer of protoplasm in a developing ovum. (b) The outer hyaline layer of protoplasm in a vegetable cell. (c) The ectosarc of protozoan. [ 1913 Webster ]