cesspool [L17th] A cesspool, in early use, meant a trap under a drain to catch solids. It is perhaps an alteration, influenced by pool, of archaic suspiral ‘vent, water pipe, settling tank’, from Old French souspirail ‘air hole’ from Latin sub- ‘from below’ and spirare ‘breathe’. Mid 19th-century cesspit was formed from cesspool. The old Irish expression bad cess meaning ‘a curse on’ is unconnected. It may be a shortening of assess (see size). In the 15th century the native Irish had to supply their English rulers with goods at prices ‘assessed’ by the government. The shortening cess then became a word for ‘tax’, indicating how fair people thought the assessment was.