A plinth is also a metal frame that is bolted to the floor. A large piece of machinery is then bolted to the plinth. As an example, the automatic gates used in the New York Subway and the London Underground mass transit systems use plinths to mount the devices. Should an entire gate need to be replaced, the plinth guarantees proper alignment and security.

Plinth (?), n. [L. plinthus, Gr. a brick or tile, a plinth, perh. akin to E. flint: cf. F. plinthe.]

(Arch.) In classical architecture, a vertically faced member immediately below the circular base of a column; also, the lowest member of a pedestal; hence, in general, the lowest member of a base; a sub-base; a block upon which the moldings of an architrave or trim are stopped at the bottom. See Illust. of Column.

© Webster 1913.