Main definitions of iris in English

: iris1Iris2



  • 1A flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center.

    • ‘Anterior uveitis, which is diagnosed by slit lamp examination, refers to inflammation of the iris and ciliary body and occurs frequently with herpes zoster ophthalmicus.’
    • ‘The middle layer is a vascular, pigmented layer consisting of the iris, ciliary body, and choroid.’
    • ‘The cornea is the clear part of the outer layer of the eye that covers the iris and the pupil.’
    • ‘Nourishment for your cornea comes from your tears and the aqueous humor - the clear fluid that fills the space between your iris and cornea.’
    • ‘It's considered superior to a circular iris in that the pupil can open wider in darkness.’
    • ‘External examination includes a penlight evaluation of the lids, conjunctiva, sclera, cornea, and iris.’
    • ‘The aqueous humour that fills the anterior chamber (front part of the eye) is produced by the ciliary body, just behind the iris.’
    • ‘The fluid made by the ciliary body (a thickening of the blood vessel tunic) inside the eye nourishes the lens and, cornea and the colored iris.’
    • ‘We know that when eyes are shut, oxygen can reach the cornea from the iris solely by way of the stagnant aqueous humor.’
    • ‘The colored circular membrane in the eye just behind the cornea is called the iris.’
    • ‘Uveitis, or inflammation of the iris, ciliary body or choroid, may also cause light sensitivity, pain and loss of vision.’
    • ‘Adhesions may also develop between the iris and cornea (peripheral anterior synechiae), covering up the trabecular drainage meshwork.’
    • ‘The walking wounded were often blind, their pupils, irises, and corneas burned out.’
    • ‘His dissection of the eye yielded the distinction between cornea, retina, iris, and chorioid coat.’
    • ‘The crystalline lens is a transparent structure situated behind the iris.’
    • ‘The cornea, the pupillary opening within the iris, the lens, and the aqueous and vitreous humor combine to form the refractive media of the eye.’
    • ‘The liquid hydrogel, based on a dendritic macromer, has optical properties similar to the cornea, the layer that covers the iris and pupil of the eye.’
    • ‘When the trabecular meshwork is blocked at the junction of the cornea and iris, the resulting rise in intraocular pressure can reach dangerously high levels and damage the optic nerve.’
    • ‘The thin sheet of circular muscle of the iris which constricts the pupil of the eye is also known as a sphincter.’
    • ‘The iridocorneal angle usually is a wide angle, is formed by the iris and the cornea, and encircles the anterior chamber.’
    1. 1.1 An adjustable diaphragm of thin overlapping plates for regulating the size of a central hole, especially for the admission of light to a lens.
      • ‘For photobleaching experiments, the iris of the microscope was reduced to the minimum diameter so that only a small region of the sample was excited.’
      • ‘Implicit in such microscopes are design elements such as solid metal alloys, high quality prisms rather than mirrors and iris diaphragms not disk type diaphragms, among others.’
      • ‘In experiments to find the effect of lens diameter he invented the familiar iris diaphragm.’
      • ‘Some of our iris diaphragms use a two-iris system to allow them to be closed completely to a zero aperture.’
      • ‘It has an iris diaphragm, and an optical and LCD screen viewfinder.’
      • ‘The incorporation of a variable iris diaphragm into the optical couplers allows the power of the beams to be independently set.’
      • ‘This is the job of the iris diaphragm, a series of overlapping metal plates that can fold in on each other or expand out.’
      • ‘This can be very problematic with small deeply housed iris diaphragms as the process tends to loosen the rest of the leaves.’
      • ‘Focusing the condenser on a microscope without an iris diaphragm is carried out by removing the slide from the stage and placing a piece of thin card half-way across the light source aperture.’
      • ‘These smooth action iris diaphragms are all fabricated in black anodized corrosion resistant frames containing spring-steel leaves.’
      • ‘These iris diaphragms are made from tempered and blackened steel leaves mounted in a metal ring.’
      • ‘Use the lever adjustment to close the field iris diaphragm until you begin to see the leaves in the viewfield.’
      • ‘It has an adjustable iris diaphragm, with up to 10 mm clear aperture, mounted in a 30 mm diameter barrel.’
      • ‘He was in the habit of using his microscope iris to adjust the valve settings on the engine of his lovingly maintained Triumph Dolomite Sprint.’
      • ‘The iris leaves of Melles Griot iris diaphragms, constructed of corrosion-resistant, blackened spring-steel, are mounted on a low-friction bearing pins.’
      • ‘These iris diaphragm valves work similar to the iris of a camera.’
      • ‘The field iris diaphragm controls the area of the circle of light illumination the specimen.’
      • ‘Consisting of a grid of iris diaphragms, the facade's surface has changing apertures.’
      • ‘The caged-probes were subsequently photoreleased in discrete regions of the cell with a 5 second UV pulse focused through an iris diaphragm.’
      • ‘Many stereomicroscopes having the parallel or common main objective design are coupled to illumination stands that are equipped with iris diaphragms.’
  • 2A plant with sword-shaped leaves and showy flowers, typically purple, yellow, or white. Native to both Eurasia and North America, it is widely cultivated as an ornamental.

    • ‘The garden includes ferns, hydrangeas, irises, waterlilies, camellias, rhododendrons, Japanese maples and fuchsias.’
    • ‘Plant reblooming irises in summer so they can root before winter.’
    • ‘Lined with turquoise tiles, the pool is surrounded by three small rectangular pools planted with irises and water lilies.’
    • ‘Daffodils, iris, tulips, gladiolus, hyacinth, and daylilies are just some of the many bulb favorites.’
    • ‘We landscaped last spring with Asian Jasmine edging, magnolias, azaleas, irises and spiral junipers next to the pool.’
    • ‘I have also seen little leaves forming on my hardy water lilies and water irises rising up above the water reaching for the sun.’
    • ‘Calla lilies, iris, geraniums and hibiscus bloomed here as well as a variety of other plants.’
    • ‘It spreads by underground fleshy stems called rhizomes; rhizomes are found on many plants, from irises to agapanthus, from ferns to Bermuda grass.’
    • ‘Some plants like ornamental grasses or irises may require knives, machetes, or even hatchets to get the job done, but it is worth it.’
    • ‘Spring-flowering bulbs such as tulips, crocuses, hyacinths, daffodils, and irises are universal symbols of spring.’
    • ‘Plants like peonies, poppies, and irises should also be planted in the fall season.’
    • ‘Michelle had painted a flower arrangement that overflowed with yellow lilies and blue irises with a fiery sunset-red background.’
    • ‘In the perennial gardens, the use of colorful and fragrant plants, including gladiolus, iris, tuberose and alstroemeria, is abundant.’
    • ‘Peonies, irises, daylilies, and delphiniums peak as phlox come into bud and astilbes begin to light up shady garden spots.’
    • ‘The newspaperman had a love for a myriad of different flower species and soon divided his interests between roses, irises, lilacs and native California plants.’
    • ‘It contains many pine trees, flower gardens, irises and ajisai in summer.’
    • ‘Do not plant irises in crowded or completely shaded areas.’
    • ‘In and alongside the stream, a different suite of plants can be found including yellow iris, hemlock water-dropwort, lesser spearwort and brooklime.’
    • ‘You can also achieve this effect by planting moisture lovers, such as cardinal flower and Japanese iris, in a bucket or a washtub or by using heavy polyethylene plastic instead of a pond liner.’
    • ‘In summer, traditional perennials take over, and peonies, irises and hemerocallis fill the flowery brook.’
  • 3A rainbow or a rainbowlike appearance.


  • no object , with adverbial of direction (of an aperture, typically that of a lens) open or close in the manner of an iris or iris diaphragm.

    • ‘Ann tugged at his arm and pointed down to the hull's underbelly: a round opening had irised out in it, brightly lit from inside.’
    • ‘A swirling vortex of yellow and white light irised open from a small dot to a man-sized portal just above the deck in front of Illeen.’
    • ‘As the last scene irised out to the familiar credits I was actually happy to have it all over.’


Modern Latin, via Latin from Greek iris ‘rainbow, iris’.




Main definitions of iris in English

: iris1Iris2


proper noun

Greek Mythology
  • The goddess of the rainbow, who acted as a messenger of the gods.