Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia, Wikipedia.
an aggregation of splanchnic mesodermal cells on the embryonic yolk sac, with the potentiality of forming vascular endothelium and primordial blood cells.
Synonym(s): blood islet
The early collections of cells in the embryo that give rise to blood and blood-forming organs later in life.
See also: island