A hair tie is a gadget used to fasten hair, particularly long hair, into a hairstyle (usually a ponytail). Hair ties are useful in securing one's hair back to keep it away from the face and to give some style to hair. Typical hair ties are round, elastic bands that are used in a very similar fashion as rubber bands.

Not to be confused with ribbon hair tie, which is a ribbon (generally non-elastic) that is used like one would use a standard hair tie.

Also not to be confused with hairpins which are clips hat are used to keep hair in place.

Example