A hex can refer to a magic spell or charm that is meant to cause harm. It is often associated with black magic or witchcraft and is used to bring bad luck or trouble to a person, place, or object. In some belief systems, a hex is considered to have a causative force in the result. The term "hex" is often used interchangeably with "curse" or "jinx". In the Pennsylvania Dutch tradition, "hex signs" are painted on barns and are commonly interpreted as having superstitious meanings, but they are actually just folk art symbols. In informal usage, "hex" can also refer to a bolt with a matching washer and hex nut.