The Collaborative International Dictionary
Cytoblast
Cytoblast \Cy"to*blast\ (s?"t?-bl?st), n. [Gr. ky`tos hollow vessel + -blast.] (Biol.) The nucleus of a cell; the germinal or active spot of a cellule, through or in which cell development takes place.
Wiktionary
cytoblast
n. (context rare English) That part of a cell (especially the nucleus) in which its development takes place