Source : Webster's Revised Unabridged Dictionary (1913)

Haematoblast \H[ae]m"a*to*blast\, n. [H[ae]mato- + -blast.]
   (Anat.)
   One of the very minute, disk-shaped bodies found in blood
   with the ordinary red corpuscles and white corpuscles; a
   third kind of blood corpuscle, supposed by some to be an
   early stage in the development of the red corpuscles; --
   called also {blood plaque}, and {blood plate}.