Columbia Encyclopedia

(Encyclopedia) ozone ōˈzōn [key], an allotropic form of the chemical element oxygen (see allotropy). Pure ozone is an unstable, faintly bluish gas with a characteristic fresh, penetrating odor. The gas has a dens...

(Encyclopedia) immunosuppressive drug, any of a variety of substances used to prevent production of antibodies. They are commonly used to prevent rejection by a recipient's body of an organ transplanted from a donor...

(Encyclopedia) curium kyo͝orˈēəm [key], artificially produced radioactive chemical element; symbol Cm; at. no. 96; mass no. of most stable isotope 247; m.p. about 1,340℃; b.p. 3,110℃; sp. gr. 13.5 (calculate...

(Encyclopedia) Red Cross, international organization concerned with the alleviation of human suffering and the promotion of public health; the world-recognized symbols of mercy and absolute neutrality are the Red Cr...

(Encyclopedia) Armada, Spanish ärmäˈdə [key], 1588, fleet launched by Philip II of Spain for the invasion of England, to overthrow the Protestant Elizabeth I and establish Philip on the English throne; also call...

(Encyclopedia) life, although there is no universal agreement as to a definition of life, its biological manifestations are generally considered to be organization, metabolism, growth, irritability, adaptation, and ...

(Encyclopedia) Mesolithic period mĕzˌəlĭthˈĭk [key] or Middle Stone Age, period in human development between the end of the Paleolithic period and the beginning of the Neolithic period. It began with the end o...

(Encyclopedia) Directory, group of five men who held the executive power in France according to the constitution of the year III (1795) of the French Revolution. They were chosen by the new legislature, by the Counc...

(Encyclopedia)  CE5 A. Cross section of a hair shaft B. General structure of a hair hair, slender threadlike outgrowth from the skin of mammals. In some animals hair grows in dense profusion and is called fur or ...

(Encyclopedia) Americas, antiquity and prehistory of the, study of the origins of the aboriginal peoples of the Americas. Archaeologists believe humans had entered and occupied much of the Americas by the end of the...