Centrosphere
Pronunciation : Cen"tro*sphere
Part of Speech : n.
Definition : 1. (Geol.)
Defn: The nucleus or central part of the earth, forming most of its mass; -- disting. from lithosphere, hydrosphere, etc.
2. (Biol.) The central mass of an aster from which the rays extend and within which the centrosome lies when present; the attraction sphere. The name has been used both as excluding and including the centrosome, and also to designate a modified mass of protoplasm about a centrosome whether aster rays are developed or not.
[Gr. centre + sphere.]
Source : Webster's Unabridged Dictionary, 1913