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in vitro fertilization

(Encyclopedia)in vitro fertilization vēˈtrō, vĭˈtrō [key] (IVF), technique for conception of a human embryo outside the mother's body. Several ova, or eggs, are removed from the mother's body and placed in sp...

extroversion and introversion

(Encyclopedia)extroversion and introversion, terms introduced into psychology by Carl Jung to identify opposite psychological types. Jung saw the activity of the extrovert directed toward the external world and tha...

conjunction, in astronomy

(Encyclopedia)conjunction, in astronomy, alignment of two celestial bodies as seen from the earth. Conjunction of the moon and the planets is often determined by reference to the sun. When a body is in conjunction ...

Lamont, Johann von

(Encyclopedia)Lamont, Johann von yōˈhän fən läˈmônt [key], 1805–79, Scottish-German astronomer and magnetician, b. Scotland. In 1817 he went to Ratisbon to study at the seminary. He remained in Germany to ...

moss, in botany

(Encyclopedia)CE5 Life cycle of a moss: A germinating spore forms a transitory branching structure on the soil surface, which develops into the conspicuous gametophyte, the familiar moss plant. Eggs and sperm ar...

mortar, in warfare

(Encyclopedia)mortar, in warfare, term originally applied to certain types of artillery with high trajectories, but later applied to an infantry weapon that consists of a tube supported by a bipod that fires a proj...

fatigue, in engineering

(Encyclopedia)fatigue, in engineering, microscopic cracking of materials, especially metals, after repeated applications of stress. Fissures may be formed within pieces of metal during their manufacture when, while...

capital, in economics

(Encyclopedia)capital, in economics, the elements of production from which an income is derived, usually defined with the exception of land and labor. As originally used in business, capital denoted interest-bearin...

rhea, in zoology

(Encyclopedia)rhea rēˈə [key], common name for a South American bird of the family Rheidae, which is related to the ostrich. Weighing from 44 to 55 lb (20–25 kg) and standing up to 60 in. (152 cm) tall, the rh...

Andromeda, in astronomy

(Encyclopedia)Andromeda, in astronomy, northern constellation located to the NE of Pegasus and to the S of Cassiopeia. Its brightest star, Alpheratz (Alpha Andromedae), marks the northeast corner of the Great Squar...