It was considered dÃ©classÃ© to refer to one's own townhouses, estates or villas (or those of friends) as mansions and modern etiquette books still advise that the terms house, big house or great house be used instead.
Waste weir. A waste weir on a navigable canal is a slatted gate on each canal level or pound, to remove excess water and to drain the canal for repairs or for the winter shutdown.
The weir crest is the top of the weir. For a v notch weir it is the point of the notch, which is the lowest point of the weir opening. The term nappe is used for the sheet of water flowing over the weir. The equations to meter flow in this article require free flow, which takes place when there is air under the nappe.