: a blastodisc after completion of cleavage and formation of the blastocoel
Word History
Etymology
earlier blastoderma, from blasto- blasto- + -derma -derma
Note: Term originated by the Baltic German embryologist and zoologist Christian Heinrich Pander (1794-1865) in Dissertatio inauguralis sistens historiam metamorphoseos, quam ovum incubatum prioribus quinque diebus subit (Würzburg, 1817), p. 21: "Praeterea enim, quod sibi sedem ac domicilium hoc deligit Embryo, ipsum quoque sua substantia ad ejus configurationem plurimum confert, quare id etiam in posterum blastoderma vocabimus." ("Moreover, because the embryo chooses this as its seat and domicile, and contributes much of its own substance to its configuration, we will henceforth call it the blastoderma.") In the German version of his dissertation (Beiträge zur Entwicklungsgeschichte des Hühnchens im Eye, Würzburg, 1817), Pander translates blastoderma as Keimhaut ("germ-skin").
First Known Use
1837, in the meaning defined above
Medical Definition
blastoderm
noun
blas·to·derm -ˌdərm
: a blastodisc after completion of cleavage and formation of the blastocoel