miosis

miosis
    n 1: (genetics) cell division that produces reproductive cells
         in sexually reproducing organisms; the nucleus divides into
         four nuclei each containing half the chromosome number
         (leading to gametes in animals and spores in plants) [syn:
         {meiosis}, {miosis}, {reduction division}]
    2: reflex contraction of the sphincter muscle of the iris in
       response to a bright light (or certain drugs) causing the
       pupil to become smaller [syn: {light reflex}, {pupillary
       reflex}, {miosis}, {myosis}]