A mass of undifferentiated cells from with an organ or body part develops

• Embryo cell group

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1849, Modern Latin, from Greek blastema "offspring, offshoot," from stem of blastanein "to shoot forth," from blastos "sprout, germ," which is of unknown origin. Related: Blastemal .

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Blastema \Blas*te"ma\, n.; pl. Blastemata . [Gr. bla`sthma bud, sprout.] (Biol.) The structureless, protoplasmic tissue of the embryo; the primitive basis of an organ yet unformed, from which it grows.

Wikipedia Word definitions in Wikipedia
A blastema is a mass of cells capable of growth and regeneration into organs or body parts. Historically, blastemas were thought to be composed of undifferentiated pluripotent cells, but recent research indicates that in some organisms blastemas may retain ...

Wiktionary Word definitions in Wiktionary
n. (context physiology English) A clump of undifferentiated cells or blasts, from which an organ or body part will develop, either during the normal growth of an embryo or in the regeneration of a lost body part.

WordNet Word definitions in WordNet
n. a mass of undifferentiated cells from which an organ or body part develops [also: blastemata (pl)]