(n.) An instrument for condensing air or other elastic fluids, consisting of a cylinder having a movable piston to force the air into a receiver, and a valve to prevent its escape.
(n.) An instrument for concentrating electricity by the effect of induction between conducting plates separated by a nonconducting plate.
(n.) A lens or mirror, usually of short focal distance, used to concentrate light upon an object.
(n.) An apparatus for receiving and condensing the volatile products of distillation to a liquid or solid form, by cooling.
(n.) An apparatus, separate from the cylinder, in which the exhaust steam is condensed by the action of cold water or air. See Illust. of Steam engine.