Biol. [mod.L., f. TETRA- + Gr. ἀστήρ star.] A karyokinetic figure formed in the modification of a cell-nucleus by the combination of four star-like masses of chromatin united by spindles or filaments.
1890. Billings, Nat. Med. Dict., Tetraster, the figure presented when there are four centres of radiation during the indirect division of a nucleus into four daughter-nuclei.
1909. J. W. Jenkinson, Exper. Embryol., 128. In the case where two sperm-nuclei unite with the egg-nucleus a tetraster is formed, that is four asters united by spindles in a square or rhombus.
