Valve, controlling flow, which has a disc at a right angle to the stem, with the valve opening and closing when it is moved up and down on the end of the stem and is often used in internal combustion engines.
Population density
Population per square mile of a given area.
Porcelain
White ceramic ware that consists of quartz, kaolin, and feldspar. It is fired at high temperature on steel or cast iron to make the surface of some bathtubs, kitchen sinks, and bathroom lavatories.
Porcelain enamel
Vitreous enamel. Often refers to pressed steel products with a porcelain glaze.
Porcelain on steel (pos)
A finish commonly used on sinks and tubs.
Porcelain tile
A ceramic mosaic tile or a paver tile that is generally made by the dust-pressed method from a composition which results in a tile that is dense, impervious, fine grained and smooth, with a sharply formed face.
Porch
An open or enclosed room on the outside of a building, which projects outward from an exterior wall.
Pore
A tiny microscopic opening, in skin, plant leaves, etc.
Porkchop
Slang for the lookout in a cornice construction.
Porosity
(1) Extent to which cavities or pores exist, allowing water to pass through. (2) Weld defect caused by small holes in the weld filler metal.
