Columbia Encyclopedia

Search results

500 results found

Mitchell, Mount

(Encyclopedia)Mitchell, Mount, peak, 6,684 ft (2,037 m) high, W N.C., in the Black Mts. of the Appalachian system; highest peak E of the Mississippi River. ...

Tien Shan

(Encyclopedia)Tien Shan, mountain system: see Tian Shan. ...

echo sounder

(Encyclopedia)echo sounder, an older instrumentation system for indirectly determining ocean floor depth. Echo sounding is based on the principle that water is an excellent medium for the transmission of sound wave...

common-ion effect

(Encyclopedia)common-ion effect, decrease in solubility of an ionic salt, i.e., one that dissociates in solution into its ions, caused by the presence in solution of another solute that contains one of the same ion...

Apennines

(Encyclopedia)Apennines ăpˈənīnz [key], Ital. Appennino, mountain system, running the entire length of the Italian peninsula. It extends south c.840 mi (1,350 km) from the Cadibona Pass in Liguria, NW Italy, wh...

multiple sclerosis

(Encyclopedia)multiple sclerosis (MS), chronic, slowly progressive autoimmune disease in which the body's immune system attacks the protective myelin sheaths that surround the nerve cells of the brain and spinal co...

norepinephrine

(Encyclopedia)norepinephrine nôrˌĕpīnĕfˈrən [key], a neurotransmitter in the catecholamine family that mediates chemical communication in the sympathetic nervous system, a branch of the autonomic nervous sys...

Brahe, Tycho

(Encyclopedia)Brahe, Tycho tīˈkō brä [key], 1546–1601, Danish astronomer. The most prominent astronomer of the late 16th cent., he paved the way for future discoveries by improving instruments and by his prec...

thymus gland

(Encyclopedia)thymus gland thīˈməs [key], mass of glandular tissue located in the neck or chest of most vertebrate animals. In humans, the thymus is a soft, flattened, pinkish-gray organ located in the upper che...

scopolamine

(Encyclopedia)scopolamine hīˈəsēnˌ, –sĭn [key], alkaloid drug obtained from plants of the nightshade family (Solanaceae), chiefly from henbane, Hyoscyamus niger. Structurally similar to the nerve substance ...