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skywriting

(Encyclopedia)skywriting, advertising medium in which aircraft spell out trade names and sales slogans in the sky by means of the controlled emission of thick smoke. The technique was first developed (1922) by J. C...

spring, in mechanics

(Encyclopedia)spring, in mechanics, any of several elastic devices used variously to store and to furnish energy, to absorb shock, to sustain the pressure between contacting surfaces, and to resist tensional or com...

prostaglandin

(Encyclopedia)prostaglandin prŏsˌtəglănˈdən [key], any of a group of about a dozen compounds synthesized from fatty acids in mammals as well as in lower animals. Prostaglandins are highly potent substances th...

pseudocoelomate

(Encyclopedia)pseudocoelomate so͞oˌdōsēˈləmātˌ [key], any of a group of invertebrates with a three-layered body that has a fluid-filled body cavity (pseudocoelom) between the endoderm and the mesoderm (the ...

weather

(Encyclopedia)weather, state of the atmosphere at a given time and place with regard to temperature, air pressure (see barometer), wind, humidity, cloudiness, and precipitation. The term weather is restricted to co...

stimulant

(Encyclopedia)stimulant, any substance that causes an increase in activity in various parts of the nervous system or directly increases muscle activity. Cerebral, or psychic, stimulants act on the central nervous s...

steam engine

(Encyclopedia)CE5 Steam engine steam engine, machine for converting heat energy into mechanical energy using steam as a medium, or working fluid. When water is converted into steam it expands, its volume increa...

poison

(Encyclopedia)poison, any agent that may produce chemically an injurious or deadly effect when introduced into the body in sufficient quantity. Some poisons can be deadly in minute quantities, others only if relati...

Duvalier, Jean-Claude

(Encyclopedia)Duvalier, Jean-Claude düvälyāˈ [key], 1951–2014, president of Haiti (1971–86). At age 19, he was proclaimed “president for life” upon the death of his father, Francois Duvalier. Under gre...

Eagleton, Thomas Francis

(Encyclopedia)Eagleton, Thomas Francis, 1929–2007, U.S. senator (1968–87), b. St. Louis, Mo. Admitted to the bar in 1953, he entered Democratic politics in Missouri and served as circuit attorney for St. Louis ...