Your iris is the colored part of your eye that surrounds the black pupil in the center. If your irises are brown, you can say you have brown eyes.
The job of the iris is to determine how large or small the pupil is, depending on the amount of light available. Your iris protects your eye's retina, by controlling how much light reaches it, and helps you to see. Another kind of iris is a bright flower with long, spiky leaves. Both irises take their names from the Greek iris, "rainbow."