(ˈ)me]z, (ˈ)mē], ]s+ noun
Etymology: mes oderm + ectoderm
: an embryonic blastomere or cell layer not yet differentiated into mesoderm and ectoderm but destined to give rise to both
• mes·ectodermal adjective
• mes·ectodermic |me]z, |mē], ]s+ adjective