sew·er·age \-rij, -rēj\noun (-s) Etymology:sewer (III) + -age 1.: sewage 2.: the systematic removal and disposal of sewage and general surface water by sewers 3.orsewerage system: the system of sewers in a city, town, or locality 4.: unclean thought or language < shocked even his fellow partisans by the sewerage he poured forth in an … address — C.G.Bowers >