a draining; a gradual flowing off of any liquid; also, that which flows out of a drain.-the mode in which the waters of a country pass off by its streams and rivers.-the system of drains and their operation, by which superfluous water is removed from towns, railway beds, mines, and other works.-area or district drained; as, the drainage of the po, the thames, etc.-the act, process, or means of drawing off the pus or fluids from a wound, abscess, etc.