blastoderm
/ˈblæstoʊdɝrm/Definitions
1. noun
A group of cells at the earliest stage of animal embryonic development, from which the rest of the embryo develops.
“The researchers studied the formation of the blastoderm in the developing chick embryo.”
2. noun
A mass of cells in the early stages of plant development, which will eventually form the embryo of a seedling.
“The seedling developed from the blastoderm in the seed.”