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ash, in botany

(Encyclopedia)ash, in botany, any plant of the genus Fraxinus of the family Oleaceae (olive family), trees and shrubs mainly of north temperate regions. The ashes are characterized by small clusters of greenish flo...

radical, in mathematics

(Encyclopedia)radical, in mathematics, symbol () placed over a number or expression, called the radicand, to indicate a root of the radicand. When used without a sign or index number, as in 4, it designates the pos...

bug, in zoology

(Encyclopedia)bug, common name correctly applied to insects belonging to the order Hemiptera, although members of the order Homoptera (e.g., mealybug) are sometimes referred to as bugs, as are other insects in gene...

nail, in carpentry

(Encyclopedia)nail, metal pin driven by force applied at one end into pieces of material, usually wood, to join them together. The strength of a nailed joint depends on the properties of the wood, the type and numb...

precipitation, in meteorology

(Encyclopedia)precipitation, in meteorology, condensed moisture that falls to the surface of the earth in the form of rain, sleet, snow, hail, frost, or dew. ...

resistance, in electricity

(Encyclopedia)resistance, property of an electric conductor by which it opposes a flow of electricity and dissipates electrical energy away from the circuit, usually as heat. Optimum resistance is provided by a con...

echo, in acoustics

(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...

heath, in botany

(Encyclopedia)CE5 Rhododendron, Rhododendron maximum, a member of the heath family heath, in botany, common name for some members of the Ericaceae, a family of chiefly evergreen shrubs with berry or capsule fru...

Atlas, in astronomy

(Encyclopedia)Atlas, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XV (or S15), Atlas is a small, irregularly shaped (nonspherical) body measuring about 25 mi (40 km) ...

Draco, in astronomy

(Encyclopedia)Draco [Lat.,=the dragon], northern constellation lying SE of Ursa Minor and N of Lyra and Hercules. It is traditionally depicted as a dragon. Draco contains the bright star Eltanin (Gamma Draconis). T...