<p><strong>Verb (used with object)</strong></p><ul><li>to withdraw or draw off (a liquid) gradually; remove slowly or by degrees, as by filtration: to drain oil from a crankcase</li><li>to withdraw liquid gradually from; make empty or dry by drawing off liquid: to drain a crankcase</li><li>to exhaust the resources of: to drain the treasury</li><li>to deprive of strength; tire</li></ul><p><strong>Verb (used without object)</strong></p><ul><li>to flow off gradually</li><li>to become empty or dry by the gradual flowing off of liquid or moisture: This land drains into the Mississippi</li></ul><p><strong>Noun</strong></p><ul><li>something, as a pipe or conduit, by which a liquid drains</li><li>a material or appliance for maintaining the opening of a wound to permit free exit of fluids</li><li>gradual or continuous outflow, withdrawal, or expenditure</li><li>something that causes a large or continuous outflow, expenditure, or depletion: Medical expenses were a major drain on his bank account</li><li>an act of draining</li><li>an artificial watercourse, as a ditch or trench</li><li>a natural watercourse modified to increase its flow of water</li></ul>