A term applied to equipment or materials which appear in an authoritative list published by an organization, such as a recognized testing laboratory.

Frequently, a regulatory authority having jurisdiction will require that only listed equipment be used in a particular location. For instance, a fire marshal may require that motor fuel dispensers installed in his territory be listed by Underwriters Laboratories, or a similar testing organization.

This means that the manufacturer of such dispensers has built the equipment in conformity with standards promulgated by the testing organization, and that the equipment has been tested by the organization.