Source : Webster's Revised Unabridged Dictionary (1913)

Entoblast \En"to*blast\, n. [Ento- + -blast.] (Biol.)
   The inner germ layer; endoderm. See {Nucleolus}.

Source : WordNet®

entoblast
     n : the inner germ layer that develops into the lining of the
         digestive and respiratory systems [syn: {endoderm}, {entoderm},
          {endoblast}, {hypoblast}]