Yes, iris is a Scrabble word!

Noun

1. Plants with sword-shaped leaves and erect stalks bearing bright-colored flowers composed of three petals and three drooping sepals

2. Muscular diaphragm that controls the size of the pupil which in turn controls the amount of light that enters the eye; it forms the colored portion of the eye

3. Diaphragm consisting of thin overlapping plates that can be adjusted to change the diameter of a central opening