Columbia Encyclopedia

(Encyclopedia) horizon, in astronomy, roughly circular line bounding an observer's view of the surface of the earth where the sky and earth seem to meet. This is the visible horizon. At sea the visible horizon is a ...

(Encyclopedia) John VIII, d. 882, pope (872–82), a Roman; successor of Adrian II. John strenuously opposed the activities of St. Ignatius of Constantinople in Bulgaria. When Ignatius died, John recognized Photius ...

(Encyclopedia) sweet potato, trailing perennial plant (Ipomoea batatas) of the family Convolvulaceae (morning glory family), native to the New World tropics. Cultivated from ancient times by the Aztecs for its edibl...

(Encyclopedia) epiphyte ĕpˈəfītˌ [key] or air plant, any plant that does not normally root in the soil but grows upon another living plant while remaining independent of it except for support (thus differing fr...

(Encyclopedia) musk, odorous substance secreted by an abdominal gland of the musk deer, used in perfume as a scent and fixative. The gland, found only in males, grows to the size of a hen's egg; the secretion is red...

(Encyclopedia) Macdonald, Dwight, 1906–82, American author and editor, b. New York City. As an associate editor (1928–36) of the business magazine Fortune he acquired a distaste for capitalism, and in 1937 he be...

(Encyclopedia) phylloxera fĭlŏkˈsĭrə [key], small, sap-eating, greenish insect of the genus Phylloxera, closely related to the aphid. Phylloxeras feed on leaves and roots, and many species produce galls on deci...

(Encyclopedia) Kremer, Michael Robert, 1964–, American economist, b. New York City, Ph.D. Harvard, 1992. After serving as a postdoctoral fellow (1992–93) at the Massachusetts Institute of Technology, he taught e...

(Encyclopedia) quadratic, mathematical expression of the second degree in one or more unknowns (see polynomial). The general quadratic in one unknown has the form ax2+bx+c, where a, b, and c are constants and x is t...

(Encyclopedia) transplanting, in horticulture, the process of removing a plant from the place where it has been growing and replanting it in another. The major requirement in transplanting (especially of larger plan...