A barrette, also known as a hair clip, hair slide or clasp, is a clasp for holding hair in place. A clasp is used to secure the barrette in place, the clasp opens when the two metal pieces at either side are pressed together.
They are used to keep hair out of the eyes, or to secure a bun, a French twist or a ponytail. Barrettes are also sometimes used purely for decorative purposes.
Larger barrettes, as long as 3-4", are designed to pull back longer hair or a large amount of hair and are usually worn at the back of the head.