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polychlorinated biphenyl

(Encyclopedia)polychlorinated biphenyl or PCB, any of a group of organic compounds originally widely used in industrial processes but later found to be dangerous environmental pollutants. Polychlorinated biphenyl i...

world soul

(Encyclopedia)world soul, Lat. anima mundi, in philosophy, term denoting a universal spirit or soul that functions as an organizing principle. While many early Greek philosophers saw the world as of one principle, ...

mordant

(Encyclopedia)mordant môrˈdənt [key] [Fr.,=biting], substance used in dyeing to fix certain dyes (mordant dyes) in cloth. Either the mordant (if it is colloidal) or a colloid produced by the mordant adheres to t...

Ratdolt, Erhard

(Encyclopedia)Ratdolt, Erhard ĕrˈhärt räˈtôlt [key], 1442–1528, printer in Venice from 1476 to 1486 and in Augsburg from 1487 to 1522. A sheet showing specimens of his sizes and designs of type, dated 1486,...

cocoa-plum

(Encyclopedia)cocoa-plum, sweet but somewhat dry fruit of the evergreen tree Chrysobalanus icaco, of the family Chyrsobalanaceae. The fruits are eaten fresh and often made into preserves. An oil used for making can...

anion

(Encyclopedia)anion ănˈīˌən [key], atom or group of atoms carrying a negative charge. The charge results because there are more electrons than protons in the anion. Anions can be formed from nonmetals by reduc...

perfluoroalkyl and polyfluoroalkyl substances

(Encyclopedia)perfluoroalkyl and polyfluoroalkyl substances (PFAS), a group of several thousand synthetic organic chemical compounds made up of a chain of carbon atoms bonded to fluorine atoms. PFAS, which resist w...

soapstone

(Encyclopedia)soapstone or steatite stēˈətīt [key], metamorphic rock of which the characteristic and usually chief mineral is talc, but which also contains varying parts of chlorite, mica, tremolite, quartz, ma...

beryl

(Encyclopedia)beryl bĕrˈĭl [key], mineral, a silicate of beryllium and aluminum, Be3Al2Si6O18, extremely hard, occurring in hexagonal crystals that may be of enormous size and are usually white, yellow, green, b...

child abuse

(Encyclopedia)child abuse, physical, sexual, or emotional maltreatment or neglect of children by parents, guardians, or others responsible for a child's welfare. Physical abuse is characterized by physical injury, ...