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scallop

(Encyclopedia)scallop or pecten, marine bivalve mollusk. Like its close relative the oyster, the scallop has no siphons, the mantle being completely open, but it differs from other mollusks in that both mantle edge...

slate

(Encyclopedia)slate, fine-grained rock formed when sedimentary rocks such as shale are metamorphosed by great pressure. Slate splits into perfectly cleaved, broad thin layers; this characteristically regular and pl...

silver chloride

(Encyclopedia)silver chloride, chemical compound, AgCl, a white cubic crystalline solid. It is nearly insoluble in water but is soluble in a water solution of ammonia, potassium cyanide, or sodium thiosulfate (“h...

North Carolina

(Encyclopedia)CE5 North Carolina, state in the SE United States. It is bordered by the Atlantic Ocean (E), South Carolina and Georgia (S), Tennessee (W), and Virginia (N). ...

dune

(Encyclopedia)dune, mound or ridge of wind-blown sand formed in arid regions and along coasts. Dunes are common in most of the great deserts of the world. Often a dune begins to form because material is deposited b...

Altai

(Encyclopedia)Altai or Altay both: ăltīˈ, äl–, ălˈtī, Rus. əltīˈ [key], geologically complex mountain system of central Asia; largely in the Altai Republic, Russia, and in Kazakhstan, but extending into...

hydrothermal vent

(Encyclopedia)hydrothermal vent, crack along a rift or ridge in the deep ocean floor that spews out water heated to high temperatures by the magma under the earth's crust. Some vents are in areas of seafloor spread...

Paleocene epoch

(Encyclopedia)Paleocene epoch pāˈlēəsēnˌ [key], first epoch of the Tertiary period in the Cenozoic era of geologic time (see geologic timescale) between 60 to 66 million years ago. In W North America, the upl...

promethium

(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...

diode

(Encyclopedia)diode dīˈōd [key], two-terminal electronic device that permits current flow predominantly in only one direction. Most diodes are semiconductor devices; diode electron tubes are now used only for a ...