. 1. (Zool.) (a) The central mass of the aster in mitotic cell division; centrosphere. (b) Less often, the mass of archoplasm left by the aster in the resting cell. [ Webster 1913 Suppl. ]

2. (Bot.) A small body situated on or near the nucleus in the cells of some of the lower plants, consisting of two centrospheres containing centrosomes. It exercises an important function in mitosis. [ Webster 1913 Suppl. ]