miosis

English

Miosis due to opiate use

Pronunciation

• IPA^(key): /maɪˈoʊsɪs/
• Homophone: meiosis
• Rhymes: -əʊsɪs

Etymology 1

Etymology tree

Proto-Indo-European *mewH-

Proto-Indo-European *mewH-ye-der.

Ancient Greek μύω (múō)

Proto-Indo-European *-tis

Proto-Hellenic *-tis

Ancient Greek -τῐς (-tĭs)

Ancient Greek -σῐς (-sĭs)

Ancient Greek -ωσις (-ōsis)bor.

New Latin -ōsislbor.

English -osis

English miosis

From Ancient Greek μύω (múō, “to close the eyes”) + English -osis.

Alternative forms

• myosis

Noun

miosis (countable and uncountable, plural mioses)

1. Contraction of the pupil of the eye.

   Antonym: mydriasis

   Horner's syndrome consists of typically unilateral miosis and eyelid ptosis, and absent forehead sweating.

Related terms

• miotic

Translations

contraction of the pupil of the eye

• Bulgarian: свиване на зеницата (svivane na zenicata)
• Catalan: miosi f
• Galician: miose (gl) f
• Greek: μύωση (el) f (mýosi)
• Italian: miosi f
• Occitan: miòsi f
• Portuguese: miose f
• Spanish: miosis f

Etymology 2

From Ancient Greek μείωσις (meíōsis).

Noun

miosis (countable and uncountable, plural mioses)

1. (obsolete) Alternative spelling of meiosis.
   • 1642, Thomas Fuller, The Holy State, Cambridge, Cambridgeshire: […] Roger Daniel for John Williams, […], →OCLC:

     Though some condemn rhetoric as the mother of lies, speaking more than the truth in hyperboles, less in her miosis, otherwise in her metaphors, contrary in her ironies, yet is there excellent use of all these […]

Spanish

Etymology

From Latin myosis, from Ancient Greek μύειν (múein) + -σις (-sis).

Noun

miosis f (plural miosis)

1. miosis

Further reading

• “miosis”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025