Columbia Encyclopedia

Search results

500 results found

proof, in mathematics

(Encyclopedia)proof, in mathematics, finite sequence of propositions each of which is either an axiom or follows from preceding propositions by one of the rules of logical inference (see symbolic logic). Mathematic...

Bandinelli, Bartolomeo

(Encyclopedia)Bandinelli, Bartolomeo bätˈchō [key], 1493?–1560, Florentine sculptor and painter; son of a goldsmith. He attempted to emulate Michelangelo, and derived from him a strong interest in musculature....

coronavirus

(Encyclopedia)coronavirus, any of a group (family Coronaviridae, subfamily Orthocoronavirinae) of enveloped single-stranded RNA viruses that have a crownlike or sunlike appearance under an electron microscope due t...

hygrometer

(Encyclopedia)hygrometer hīgrŏmˈətər [key], instrument used to measure the moisture content of a gas, as in determining the relative humidity of air. The temperature at which dew or frost forms is a measure of...

heart, artificial

(Encyclopedia)heart, artificial, external or surgically implanted mechanical device designed to replace a patient's diseased heart. The first one used on a human being, the Jarvik-7, was implanted (1982) in Barney ...

Holocene epoch

(Encyclopedia)Holocene epoch hŏlˈəsēn [key] or Recent epoch, most recent of all subdivisions of geologic time, ranging from the present back to the time (c.11,000 years ago) of almost complete withdrawal of the...

automation

(Encyclopedia)automation, automatic operation and control of machinery or processes by devices, such as robots that can make and execute decisions without human intervention. The principal feature of such devices i...

language acquisition

(Encyclopedia)language acquisition, the process of learning a native or a second language. The acquisition of native languages is studied primarily by developmental psychologists and psycholinguists. Although how c...

aging

(Encyclopedia)aging, in biology, cumulative changes in an organism, organ, tissue, or cell leading to a decrease in functional capacity. In humans, aging is associated with degenerative changes in the skin, bones, ...

cave

(Encyclopedia)cave, a cavity in the earth's surface usually large enough for a person to enter. Caves may be formed by the chemical and mechanical action of a stream upon soluble or soft rock, of rainwater seeping ...