Excessive contraction of the pupil

• The nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants)
• Reproductive cell division
• (genetics) cell division that produces reproductive cells in sexually reproducing organisms
• Excessive pupil constriction
• Reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller

WordNet Word definitions in WordNet
n. (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 , reduction ...

Wiktionary Word definitions in Wiktionary
n. Contraction of the pupil of the eye.

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1819, from Greek myein "to shut (the eyes)" + -osis . Greek myein is perhaps originally "to close the lips," from PIE *meue- "to be silent" (see mute (adj.)). Related: Miotic .

Wikipedia Word definitions in Wikipedia
Miosis or myosis , /maɪˈoʊ sɪs/, from Ancient Greek μύειν, mūein , "to close the eyes", is a term with various definitions, which generally include constriction of the pupil . The opposite condition, mydriasis , is the dilation of the pupil . Anisocoria ...