noun.
A small region of cytoplasm adjacent to the nucleus that contains the centrioles and serves to organize microtubules.
The Century Dictionary and Cyclopedia
noun.
In cytology, a body of indeterminate nature in the center of each astrosphere of the dividing-cell.
the GNU version of the Collaborative International Dictionary of English
noun.
A peculiar rounded body lying near the nucleus of a cell. It is regarded as the dynamic element by means of which the machinery of cell division is organized.