iris1
/ˈʌɪrɪs
/noun
1A flat, coloured, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the centre.The thin sheet of circular muscle of the iris which constricts the pupil of the eye is also known as a sphincter....
- The walking wounded were often blind, their pupils, irises, and corneas burned out.
- The colored circular membrane in the eye just behind the cornea is called the iris.
1.1 (also iris diaphragm) An adjustable diaphragm of thin overlapping plates for regulating the size of a central hole, especially for the admission of light to a lens.The incorporation of a variable iris diaphragm into the optical couplers allows the power of the beams to be independently set....
- In experiments to find the effect of lens diameter he invented the familiar iris diaphragm.
- This is the job of the iris diaphragm, a series of overlapping metal plates that can fold in on each other or expand out.
2A plant with showy flowers, typically of purple or yellow, and sword-shaped leaves. Irises are native to both Eurasia and North America and widely cultivated as ornamentals.
- Genus Iris, family Iridaceae (the iris family): many species and numerous hybrids. The iris family also includes the gladioli, crocuses, and freesias.
- It spreads by underground fleshy stems called rhizomes; rhizomes are found on many plants, from irises to agapanthus, from ferns to Bermuda grass.
- Daffodils, iris, tulips, gladiolus, hyacinth, and daylilies are just some of the many bulb favorites.
verb [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.
Origin
Modern Latin, via Latin from Greek iris 'rainbow, iris'.
In classical mythology Iris was the goddess of the rainbow and a messenger of the gods. People saw the rainbow as a bridge or road let down from heaven for her to carry her messages along. The Latin and Greek word iris, taken from her name and meaning ‘rainbow’, is also in iridescent and the name of the chemical element iridium, which forms compounds of various colours. The name iris for the membrane behind the cornea of the eye appears to derive from the variety of its colours. As a name for a flowering plant, iris dates from the late Middle Ages.
Rhymes
Iris2
/ˈʌɪrɪs/Greek Mythology
The goddess of the rainbow, who acted as a messenger of the gods.