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soil

(Encyclopedia)soil, surface layer of the earth, composed of fine rock material disintegrated by geological processes; and humus, the organic remains of decomposed vegetation. In agriculture, soil is the medium that...

comet

(Encyclopedia)CE5 Comet: Whatever the direction of a comet's flight, its “tail” always points away from the sun. The tail disappears when the comet is far from the sun. comet [Gr.,=longhaired], a small cele...

school

(Encyclopedia)school, term commonly referring to institutions of pre-college formal education. It also properly includes colleges, universities, and many types of special training establishments (see adult educatio...

elephantiasis

(Encyclopedia)elephantiasis ĕlˈəfăntīˈəsĭs [key], abnormal enlargement of any part of the body due to obstruction of the lymphatic channels in the area (see lymphatic system), usually affecting the arms, le...

diffraction

(Encyclopedia)diffraction, bending of waves around the edge of an obstacle. When light strikes an opaque body, for instance, a shadow forms on the side of the body that is shielded from the light source. Ordinarily...

milling

(Encyclopedia)milling, mechanical grinding of wheat or other grains to produce flour. Milling separates the fine, mealy parts of grain from the fibrous bran covering. In prehistoric times grain was crushed between ...

lamprey

(Encyclopedia)lamprey, name for several primitive marine and freshwater jawless fishes of the order Petromyzontiformes. As in the other jawless fish, the hagfish, the adult lamprey retains the notochord, the suppor...

3D printer

(Encyclopedia)3D printer, computerized device that produces a three-dimensional object by creating it as a series of thin layers. The object is created from a model stored in computer-aided design file; the model i...

berkelium

(Encyclopedia)berkelium bûrˈklēəm [key] [from Berkeley], artificially produced radioactive chemical element; symbol Bk; at. no. 97; mass no. of most stable isotope 247; m.p. about 1,050℃; b.p. about 2,590℃;...

acoustics

(Encyclopedia)acoustics əko͞oˈstĭks [key] [Gr.,=the facts about hearing], the science of sound, including its production, propagation, and effects. Various branches of acoustics that deal with different aspects...