1. (n.) A gradual flowing off of any liquid; also, that which flows out of a drain\.

2. (n.) The mode in which the waters of a country pass off by its streams and rivers.

3. (n.) The system of drains and their operation, by which superfluous water is removed from towns, railway beds, mines, and other works.

4. (n.) Area or district drained; as, the drainage of the Po, the Thames, etc.

5. (n.) The act, process, or means of drawing off the pus or fluids from a wound, abscess, etc.

air-drying anhydration aspiration bleeding bloodletting broaching cleaning out clearance clearing cupping defecation defluxion dehumidification dehydration depletion desiccation discharge discharging cargo drafting drain draining drawing drying drying up effluence efflux effluxion effusion egress elimination emptying evacuation evaporation excretion exhalation exhaust exhausting exhaustion flowoff gush insolation milking mummification off-loading outfall outflow outflowing outpour outpouring phlebotomy pipetting pumping removal runoff siphoning sucking suction tapping unloading venesection venting voidance voiding withering