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(Encyclopedia)porcupine, member of either of two rodent families, characterized by having some of its hairs modified as bristles, spines, or quills. The quills are loosely attached to the porcupines' skin and pull ...

pitch, in aviation

(Encyclopedia)pitch, in aviation: see airplane; airfoil. ...

pitch, in music

(Encyclopedia)pitch, in music, the position of a tone in the musical scale, today designated by a letter name and determined by the frequency of vibration of the source of the tone. Pitch is an attribute of every m...

plum, in botany

(Encyclopedia)plum, common name for a tree of any of many species of the genus Prunus of the family Rosaceae (rose family) and for its fruit, a drupe. The plum is generally cultivated in the temperate zones, though...

power, in mathematics

(Encyclopedia)power, in mathematics: see exponent. ...

power, in physics

(Encyclopedia)power, in physics, time rate of doing work or of producing or expending energy. The unit of power based on the English units of measurement is the horsepower, devised for describing mechanical power b...

precipitation, in chemistry

(Encyclopedia)precipitation, in chemistry, a process in which a solid is separated from a suspension, sol, or solution. In a suspension such as sand in water the solid spontaneously precipitates (settles out) on st...

precipitation, in meteorology

(Encyclopedia)precipitation, in meteorology, condensed moisture that falls to the surface of the earth in the form of rain, sleet, snow, hail, frost, or dew. ...

pike, in zoology

(Encyclopedia)pike, common name for the family Esocidae, freshwater game and food fishes of Europe, Asia, and North America. The pike, the muskellunge, and the pickerel form a small but well-known group of long, th...