iris

• Nom désignant un genre de plantes à fleurs aux pétales vifs et aux sépales retombants ; également le diaphragme musculaire coloré de l'œil qui contrôle la taille de la pupille ; et un diaphragme mécanique à ouverture réglable utilisé en optique.

A noun referring to a genus of flowering plants with showy petals and drooping sepals; also the colored muscular diaphragm of the eye that controls pupil size; and a mechanical diaphragm with adjustable opening used in optics.

1. Ornamental flowering plantB1formal

   A perennial plant with sword-shaped leaves and erect stalks bearing bright-colored flowers, typically having three petals and three drooping sepals.

   Iris (plante)

   • Irises bloom in late spring and add vibrant color to gardens.
   • She planted a row of purple irises along the fence.
   • The iris is a popular ornamental flower in many cultures.
   • Dutch painters often depicted irises in their still-life artwork.

   Synonymesflag

2. Colored part of the eyeB2formalmedical

   The muscular diaphragm of the eye that controls the size of the pupil, regulating the amount of light entering and also determining eye color.

   Iris (anatomie de l'œil)

   • Her irises are a striking shade of green.
   • The doctor examined the patient's iris for signs of inflammation.
   • In dim light, the iris expands the pupil to let in more light.
   • Eye color is determined by the pigmentation of the iris.

3. Adjustable diaphragm in opticsC1formaltechnical

   A device made of thin overlapping plates that can be adjusted to change the diameter of a central aperture, controlling the amount of light passing through a lens.

   Diaphragme à iris

   • The camera's iris adjusts automatically to changing light conditions.
   • Photographers manually set the iris to control depth of field.
   • Modern lenses have a multi-blade iris for smoother bokeh.
   • The telescope's iris limits stray light for clearer observations.

   Synonymesdiaphragm