miosis

n. constriction of the pupil (Medicine)

Miosis should not be confused with meiosis, the cellular division process involved in sexual reproduction, or mitosis, the cellular division of somatic body cells. Miosis is a medical term for constriction of the pupil. It is the opposite of mydriasis. It is seen in a variety of medical conditions, and can also be caused by certain drugs and chemicals. Eye drops used to intentionally cause miosis are known as "miotics". Extreme miosis is commonly called "pinpoint pupils", a situation that can be caused by use of opiates.
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Miosis /mi·o·sis/ contraction of the pupil. mi·o·sis or my·o·sis n. pl. mi·o··ses 1. The period of decline of a disease in which the intensity of [more]Miosis - Community and Resources

Noun
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)
(synonym) meiosis, reduction division
(hypernym) cell division, cellular division
(hyponym) nondisjunction
(part-meronym) anaphase
(classification) genetics, genetic science
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
(synonym) light reflex, pupillary reflex, myosis
(hypernym) reflex, instinctive reflex, innate reflex, inborn reflex, unconditioned reflex, physiological reaction

Contraction of the pupil. The opposite of mydriasis.