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chrysoberyl

(Encyclopedia)chrysoberyl krĭsˈəbĕrˌĭl [key] [Gr.,=golden beryl], a beryllium aluminate used as a gem. It has a vitreous luster and is transparent to translucent. The more valuable cat's-eye is a variety of c...

Esperanto

(Encyclopedia)Esperanto ĕspəränˈtō [key], an artificial language introduced in 1887 and intended by its inventor, Dr. Ludwik Lejzer Zamenhof (1859–1917), a Polish oculist and linguist, to ease communication ...

Negro, Río, river, Uruguay and Brazil

(Encyclopedia)Negro, Río rēˈō nāˈgrō [key], principal river of Uruguay, c.500 mi (800 km) long, rising in S Brazil and flowing SW across central Uruguay to the Uruguay River. It traverses a sheep-raising reg...

castor oil

(Encyclopedia)castor oil, yellowish oil obtained from the seed of the castor bean. The oil content of the seeds varies from about 20% to 50%. After the hulls are removed the seeds are cold-pressed. Medicinal castor...

Mogilev

(Encyclopedia)Mogilev məgēlyôfˈ [key], Belarusian Mahilyow, city (1989 pop. 359,188), capital of Mogilev region, in E Belarus, on the Dnieper River. It is an important rail and highway junction, a river port, a...

Hahn, Otto

(Encyclopedia)Hahn, Otto ôˈtō hän [key], 1879–1968, German chemist and physicist. His important contributions in the field of radioactivity include the discovery of several radioactive substances, the develop...

Ives, Frederic Eugene

(Encyclopedia)Ives, Frederic Eugene, 1856–1937, American inventor, b. Litchfield, Conn. A pioneer in the development of orthochromatic and trichromatic photography and of photoengraving, he followed an earlier su...

denture

(Encyclopedia)denture, artificial replacement for natural teeth and surrounding tissue. Dentures are classified as partial or complete. The former are removable and maintained by clasps, or are fixed bridges with c...

shamrock

(Encyclopedia)shamrock, a plant with leaves composed of three leaflets. According to legend it was used by St. Patrick in explaining the doctrine of the Trinity; it is now used as the emblem of Ireland. An artifici...

Tsiolkovsky, Konstantin Eduardovich

(Encyclopedia)Tsiolkovsky, Konstantin Eduardovich kənstəntyēnˈ ĕdwärˈdəvĭchˈ tsēōlkŏvˈskē [key], 1857–1935, Russian inventor and rocket expert. He lost his hearing in childhood, and, as he could no...