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