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time , in music

(Encyclopedia)time, in music: see tempo; meter; rhythm; syncopation; metronome and musical notation. ...

ray, in physics

(Encyclopedia)ray, in physics, term denoting the straight line along which light or other form of radiation is propagated from its source. It generally refers to the line of propagation of waves but is also applied...

periwinkle, in zoology

(Encyclopedia)periwinkle, any of a group of marine gastropod mollusks having conical, spiral shells. Periwinkles feed on algae and seaweed. They are found at the water's edge; out of water, they resist drying by cl...

eclecticism, in philosophy

(Encyclopedia)eclecticism ĭklĕkˈtĭsĭzˌəm [key] [Gr. eklektikos=to choose], in philosophy, the selection of elements from different systems of thought, without regard to possible contradictions between the sy...

sublimation, in chemistry

(Encyclopedia)sublimation sŭblĭmāˈshən [key], change of a solid substance directly to a vapor without first passing through the liquid state. The term is also used to describe the reverse process of the gas ch...

Al-Battani

(Encyclopedia)Al-Battani ălˌbətēˈnēəs [key], b. before 858, d. 929, Arab astronomer and mathematician. He is best known in astronomy for his improvements and corrections of the Ptolemaic tradition. His Kitab...

occultation

(Encyclopedia)occultation ŏkˌəltāˈshən [key], in astronomy, eclipse of one celestial body by another, e.g., when the moon lies between a star and the earth. Occultations of stars by the moon are important in ...

columbine, in botany

(Encyclopedia)columbine kŏlˈəmbīn [key], any plant of the genus Aquilegia, temperate-zone perennials of the family Ranunculaceae (buttercup family), popular both as wildflowers and as garden flowers. Columbines...

earth, in chemistry

(Encyclopedia)earth, in chemistry, metallic oxide not readily reducible by chemical means, e.g., alkaline earths, rare earths, and alumina. The name is also applied to certain absorbent clays, e.g., fuller's earth,...

astrophysics

(Encyclopedia)astrophysics, application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. The distinctio...