1. [ noun ] (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: reduction_division meiosis
Related terms: cell_division nondisjunction segregation anaphase metaphase telophase karyokinesis prophase genetics
2. [ noun ] (biology,medicine) reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller
Synonyms: myosis pupillary_reflex light_reflex
Related terms: reflex
Similar spelling:   missis