the world > physical sensation > cleanness and dirtiness > clearing of refuse matter > [noun] > clearing drain or sewer (9)
The action of flush, v.2 in various senses. The cleansing (of a sewer, etc.) by a rush of water.
The act of cleansing (a drain) by flushing.
The action or process of pushing a rod or rods through a duct, drain, or pipe, esp. in order to clear it. Cf. rod, v. 4.