Definition of blastodisk in US English:
 blastodisk
(also blastodisc)
nounˈblastəˌdiskˈblastəˌdisk
Embryology A blastula having the form of a disk of cells on top of the yolk in the eggs of reptiles and birds.
Example sentencesExamples
-  Yolk syncytial nuclei originated from the deepest, open cells beneath the blastodisk.
 -  The blastodisks were located, removed aseptically, and stored in cryovials at - 80 C for DNA analysis.
 -  Note the blastula in reptiles is called a blastoderm or blastodisk because the divisions have been concentrated into a thin disk of cells at the animal pole.
 -  At 38 minutes after insemination, the first cleavage was observed and the first cleavage furrow of the blastodisk appeared at 53 minutes.
 -  In amniotes, the embryo develops in a blastodisk atop a large yolk mass.