transitive verb

1. to draw off (liquid) gradually
2. to draw water or any liquid from gradually so as to dry or empty to drain swamps
3. to receive the waters of the St. Lawrence drains the Great Lakes
4. to drink all the liquid from (a cup, glass, etc.)
5. to exhaust (strength, emotions, or resources) gradually
6. Obsolete to filter

Etymology: ME dreinen < OE dreahnian, to strain off, lit., to dry out < base of dryge, dry

intransitive verb

1. to flow off gradually
2. to become dry by the drawing or flowing off of liquid
3. to disappear gradually his courage drained away
4. to discharge its waters central Europe drains into the Danube

noun

1. a channel or pipe for carrying off water, sewage, etc.
2. a draining or exhausting
3. that which gradually exhausts strength, resources, etc.
4. Surgery a tube or other device for drawing off discharge, fluid, etc. from a cavity, wound, etc.