Depending on the style, a garter belt is worn at the waist, or slightly lower on the hips. Some styles are simple bands of lace and elastic, worn with a separate panty, while others include a built-in panty in addition to the garter straps.
Garter belts are used to hold up thigh-high stockings. Initially, they were a necessity, as stockings were made of nylon. Since they didn't contain elastic, they could not stay up on their own. Current thigh-high stockings contain Lycra and other performance fabrics to help keep them in place. They also have silicone and/or elastic grips at the top, which accomplish the same purpose.
Western wedding traditions are one area where garter use continues. In this tradition, the bride wears a garter, usually either white or blue, that the groom removes at the end of the reception. The garter removal is done with sensuality and fanfare, as a prelude to wedding night intimacy. Once removed, the groom tosses the garter into the crowd of bachelors at the reception, similar to the way the bride tosses her bouquet to the single women. Tradition holds that the woman who catches the bouquet and the man who catches the garter have the next dance together.