ep·i·blast \ˈepəˌblast\noun (-s) Etymology:epi- + -blast 1.: the outer layer of the blastoderm : ectoderm — compare germ layer 2.: a small outgrowth shaped like a claw that lies in front of the plumule and opposite the scutellum in many grasses and has been considered to be a second cotyledon • ep·i·blas·tic\|epə̇|blastik\adjective