TRAP n. 2 definitions
A bend, sag, or partitioned chamber, in a drain, soil pipe, sewer, etc., arranged so that the liquid contents form a seal which prevents passage of air or gas, but permits the flow of liquids.
WASH n.
Substances collected and deposited by the action of water; as, the wash of a sewer, of a river, etc. The wash of pastures, fields, commons, and roads, where rain water hath a long time settled. Mortimer.