Definition of "drainage"

drainage

/ˈdɹeɪnəd͡ʒ/

noun
countable and uncountable, plural drainages
1. A natural or artificial means for the removal of fluids from a given area by its draining away.
  Quotations
  It should move NR away from previous examples of repairs that have treated the symptoms (fixing the landslip) but not fixed the underlying cause (poor drainage), with the result that a second slip followed.
  2023 June 14, Philip Haigh, “Landslips: NR strives to turn back the tide”, in RAIL, number 985, page 35
2. A system of drains.
3. A downward wind.
  Quotations
  In the forward part of the cyclone, drainage katabasis is checked; but its highest intensity is observed in the rear part of the cyclone.
  1960, N. P. Rusin, “The Radiation Balance of the Snow Surface of Antarctica”, in OG Krichak, editor, Scientific Conference on Problems of Meteorology of the Antarctic (Abstracts of Reports)(USSR)., page 29