Definitions for garter belt
Random House Webster's College Dictionary
an undergarment of cloth or elastic, with attached garters, worn by women to hold up stockings.
Origin of garter belt:
garter belt, suspender belt(noun)
a wide belt of elastic with straps hanging from it; worn by women to hold up stockings
An item of women's underwear consisting of a belt to which are attached garters for holding up stockings; suspender belt.