∙ The practice of exploring drains, tunnels, or sewers. uncountable
∙ The liquid drained from something. countable, chiefly plural
drain
Noun
∙ A conduit allowing liquid to flow out of an otherwise contained volume.
∙ An access point or conduit for rainwater that drains directly downstream in a (drainage) basin without going through sewers or water treatment in order to prevent or belay floods. chiefly Britain
∙ Something consuming resources and providing nothing in return.
∙ An act of urination. vulgar
∙ The name of one terminal of a field effect transistor (FET). electronics
∙ An outhole. pinball
Verb
∙ To lose liquid. intransitive
∙ To flow gradually. intransitive
∙ To cause liquid to flow out of. transitive, ergative
∙ To convert a perennially wet place into a dry one. transitive, ergative
∙ To deplete of energy or resources. transitive
∙ To draw off by degrees; to cause to flow gradually out or off; hence, to exhaust. transitive
∙ To filter. transitive, obsolete
∙ To fall off the bottom of the playfield. intransitive, pinball