blastocoel

from WordNet (r) 3.0 (2006)

blastocoel
    n 1: the fluid-filled cavity inside a blastula [syn:
         {blastocoel}, {blastocoele}, {blastocele}, {segmentation
         cavity}, {cleavage cavity}]

from The Collaborative International Dictionary of English v.0.48

blastocoel \blastocoel\, Blastocoele \Blas"to*c[oe]le\
blastocoele \blastocoele\, n. [Gr. blasto`s sprout + koi^los
   hollow.] (Biol.)
   The cavity inside a blastula; -- also called {segmentation
   cavity}.
   [1913 Webster]