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hydrogenation

(Encyclopedia)hydrogenation hīdrôjˈənāˌshən, hīˌdrəjənāˈshən [key], chemical reaction of a substance with molecular hydrogen, usually in the presence of a catalyst. A common hydrogenation is the harde...

homology

(Encyclopedia)CE5 Homology in bones of a bird wing and an amphibian foreleg homology hōmŏlˈəjē [key], in biology, the correspondence between structures of different species that is attributable to their ev...

fumitory

(Encyclopedia)CE5 Climbing fumitory, Adlumia fungosa fumitory, common name for some members of the Fumariaceae, a family of herbs native to much of the Old World, especially temperate Eurasia. The family is clo...

mansard roof

(Encyclopedia)CE5 Mansard roof mansard roof mănˈsärd [key], type of roof, so named because it was frequently used by the French architect François Mansart. It was not devised by him but was used early in th...

arginine

(Encyclopedia)CE5 arginine ärˈjənĭn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of proteins. Its basic side ...

panpipes

(Encyclopedia)CE5 Panpipes panpipes, Pandean pipes sĭrˈĭngks [key], musical wind instrument, consisting of graduated tubes closed at one end and fastened together. The player holds the instrument vertically...

ziggurat

(Encyclopedia)CE5 Ziggurat ziggurat zĭgˈo͝orăt [key], form of temple common to the Sumerians, Babylonians and Assyrians. The earliest examples date from the end of the 3d millenium b.c., the latest from the...

pyrimidine

(Encyclopedia)CE5 Pyrimidines found in deoxyribonucleic acid (DNA) pyrimidine pīrĭmˈĭdēnˌ [key], type of organic base found in certain coenzymes and in the nucleic acids of plant and animal tissue. The th...

‘Oumuamua

(Encyclopedia)‘Oumuamua ōmo͞oˈəmo͞oˈə [key], officially 1I/2017 U1 (‘Oumuamua), interstellar object, the first to be discovered in the solar system. Highly variable in brightness, it also is highly and u...

cysteine

(Encyclopedia)CE5 CE5 cysteine sĭsˈtēn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer participates in the biosynthesis of mammalian protein...