miosis

Noun (2)

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)Synonyms: meiosisreduction 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 smallerSynonyms: light reflexpupillary reflexmyosis