Hair tie
A hair tie (or "hair up", hairband, ponytail holder, hair elastic, rubber band, ponytailer, hairbow, or bobble) is a gadget used to fasten hair, particularly long hair, into a hairstyle (usually a ponytail). Two kinds of hair tie are the scrunchie and the hairpin. Hair ties are useful in securing one's hair back to keep it away from the face and to give some style to hair. When using a hair tie as a rubber band-like weapon by "shooting" it at some person, animal, or object it is not uncommon for the metal brace to slam the one doing the "shooting" in the cuticle. This backfire of sorts is very painful. Different hair bands are made from different materials. Some are mainly made of a stretchy type of cotton; some are made of elastic and rubber. Because they are made of different materials, they will have different durability and elasticity rates.
Another term is a "hair binder" (commonly used in Minnesota). "Hair binder" is commonly used throughout the United States.