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gnat

(Encyclopedia)gnat, common name for any one of a number of small, fragile-looking two-winged flies of the suborder Nematocera, order Diptera, which includes the families Tipulidae (crane flies), Bibionidae (hairfli...

Tula , ancient city, Mexico

(Encyclopedia)Tula to͞oˈlä [key], ancient city in the present state of Hidalgo, central Mexico. It was one of the chief urban centers of the Toltec. The city is believed to be Tollán, the legendary Toltec capit...

Almoravids

(Encyclopedia)Almoravids ălmôrˈəvĭdz [key], Berber Muslim dynasty that ruled Morocco and Muslim Spain in the 11th and 12th cent. The Almoravids may have originated in what is now Mauritania. The real founder w...

White Nile

(Encyclopedia)White Nile, river, one of the chief tributaries of the Nile, E Africa. The name is sometimes used for the 600 mi (970 km) long section of the river known as the Bahr el Abiad that extends upstream fro...

banana

(Encyclopedia)banana, name for several species of the genus Musa and for the fruits these produce. The banana plant—one of the largest herbaceous plants—is native to tropical Asia but now cultivated throughout ...

cycad

(Encyclopedia)cycad sīˈkăd [key], any plant of the order Cycadales, tropical and subtropical palmlike evergreens. The cycads, ginkgoes, and conifers comprise the three major orders of gymnosperms, or cone-bearin...

Lycopodiophyta

(Encyclopedia)Lycopodiophyta līˌkōpōˌdēŏfˈətə [key], division of the plant kingdom consisting of the organisms commonly called club mosses and quillworts. As in other vascular plants, the sporophyte, or s...

United Nations Conference on Environment and Development

(Encyclopedia)United Nations Conference on Environment and Development (UNCED) or Earth Summit, an 11-day meeting held in June, 1992, in Rio de Janeiro, Brazil, to discuss the global conflict between economic devel...

hemp

(Encyclopedia)hemp, common name for a tall annual herb (Cannabis sativa) of the family Cannabinaceae, native to Asia but now widespread because of its formerly large-scale cultivation for the bast fiber (also calle...

blood bank

(Encyclopedia)blood bank, site or mobile unit for collecting, processing, typing, and storing whole blood, blood plasma and other blood constituents. Most hospitals maintain their own blood reserves, and the Americ...