Columbia Encyclopedia

(Encyclopedia) mixture, in chemistry, a physical combination of two or more pure substances (i.e., elements or compounds). A mixture is distinguished from a compound, which is formed by the chemical combination of t...

(Encyclopedia) West Nile virus, microorganism and the infection resulting from it, which typically produces no symptoms or a flulike condition. The virus is a flavivirus and is related to a number of viruses that ca...

(Encyclopedia) dividend, that part of the net earnings of a corporation that is distributed to its stockholders. Dividend disbursements are based on a percentage of the par value of the stock or are a certain sum pe...

(Encyclopedia) dynamics, branch of mechanics that deals with the motion of objects; it may be further divided into kinematics, the study of motion without regard to the forces producing it, and kinetics, the study o...

(Encyclopedia) coma, in medicine, deep state of unconsciousness from which a person cannot be aroused even by painful stimuli. The patient cannot speak and does not respond to command. Coma is the result of damage t...

(Encyclopedia) edema ĭdēˈmə [key], abnormal accumulation of fluid in the body tissues or in the body cavities causing swelling or distention of the affected parts. Edema of the ankles and lower legs (in ambulato...

(Encyclopedia) incest, sexual relations between persons to whom marriage is prohibited by custom or law because of their close kinship. Ideas of kinship, however, vary widely from group to group, hence the definitio...

(Encyclopedia) franchise, in government, a right specifically conferred on a group or individual by a government, especially the privilege conferred by a municipality on a corporation of operating public utilities, ...

(Encyclopedia) Johnson, Boris (Alexander Boris de Pfeffel Johnson), 1964–, British political leader, b. New York City, grad. Oxford (1986). While at Oxford Johnson was president of the prestigious Oxford Union deb...

(Encyclopedia) quelea kwēˈlēə [key], common name for an East African weaverbird, Quelea quelea. Less than 5 in. (13 cm) long and weighing slightly more than 1⁄2 oz (1.4 grams), these tiny birds are found throu...