from
The Collaborative International Dictionary of English v.0.48
Drainage \Drain"age\, n.
1. A draining; a gradual flowing off of any liquid; also,
that which flows out of a drain.
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2. The mode in which the waters of a country pass off by its
streams and rivers.
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3. (Engin.) The system of drains and their operation, by
which superfluous water is removed from towns, railway
beds, mines, and other works.
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4. Area or district drained; as, the drainage of the Po, the
Thames, etc. --Latham.
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5. (Surg.) The act, process, or means of drawing off the pus
or fluids from a wound, abscess, etc.
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{Drainage tube} (Surg.), a tube introduced into a wound,
etc., to draw off the discharges.
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