Source : Webster's Revised Unabridged Dictionary (1913)

Periblast \Per"i*blast\, a. [Gr. ? to grow around. See {Peri-},
   and {-blast}.] (Biol.)
   The protoplasmic matter which surrounds the entoblast, or
   cell nucleus, and undergoes segmentation. --
   {Per`i*blas"tic}, a.