rad

the unit of plane angle adopted under the Systeme International d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees) ; a unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material ;

radar

measuring instrument in which the echo of a pulse of microwave radiation is used to detect and locate distant objects ;

radar beacon

a device that, on receiving radar signals, transmits coded signals in response to help navigators determine their position ;

radar dome

a housing for a radar antenna; transparent to radio waves ;

radar echo

an electronic signal that has been reflected back to the radar antenna; contains information about the location and distance of the reflecting object ;

radar fire

gunfire aimed a target that is being tracked by radar ;

radar target

a radar echo displayed so as to show the position of a reflecting surface ;

radclyffe hall

English writer whose novel about a lesbian relationship was banned in Britain for many years (1883-1943) ;

raddle

a red iron ore used in dyeing and marking ;

radhakrishnan

Indian philosopher and statesman who introduced Indian philosophy to the West (1888-1975) ;

radial

pneumatic tire that has radial-ply casing ;

radial-ply tire

pneumatic tire that has radial-ply casing ;

radial artery

branch of the brachial artery beginning below the elbow and extending down the forearm around the wrist and into the palm ;

radial asymmetry

the absence of symmetry about an axis ;

radial engine

an internal-combustion engine having cylinders arranged radially around a central crankcase ;

radial keratotomy

radial pattern of incisions in the cornea that cause the cornea to bulge; performed to correct myopia ;

radial nerve

largest branch of the brachial plexus; extends down the humerus to the lateral epicondyle where it divides into one branch that goes to the skin on the back of the hand and another that goes to the underlying extensor muscles ;

radial pulse

pulse of the radial artery (felt in the wrist) ;

radial symmetry

the property of symmetry about an axis; "the starfish illustrates radial symmetry" ;

radial tire

pneumatic tire that has radial-ply casing ;

radial vein

superficial veins ascending the radial side of the forearm; combines with the ulnar veins to form the brachial vein ;

radial velocity

velocity along the line of sight toward or away from the observer ;

radian

the unit of plane angle adopted under the Systeme International d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees) ;

radiance

the quality of being bright and sending out rays of light ; the amount of electromagnetic radiation leaving or arriving at a point on a surface ; an attractive combination of good health and happiness; "the radiance of her countenance" ;

radiancy

the quality of being bright and sending out rays of light ;

radiant energy

energy that is transmitted in the form of (electromagnetic) radiation; energy that exists in the absence of matter ;

radiant flux

the rate of flow of radiant energy (electromagnetic waves) ;

radiant heating

heating a building by radiation from panels containing hot water or electrical heaters ;

radiation

(medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance ; the act of spreading outward from a central source ; a radial arrangement of nerve fibers connecting different parts of the brain ; the spread of a group of organisms into new habitats ; energy that is radiated or transmitted in the form of rays or waves or particles ; the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay ; syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours; "he was suffering from radiation" ;

radiation diagram

graphical representation (in polar or Cartesian coordinates) of the spatial distribution of radiation from an antenna as a function of angle ;

radiation field

a field that represents the energy lost from the radiator to space ;

radiation pattern

graphical representation (in polar or Cartesian coordinates) of the spatial distribution of radiation from an antenna as a function of angle ;

radiation pressure

the minute pressure exerted on a surface normal to the direction of propagation of a wave ;

radiation pyrometer

a pyrometer for estimating the temperature of distant sources of heat; radiation is focussed on a thermojunction connected in circuit with a galvanometer ;

radiation sickness

syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours; "he was suffering from radiation" ;

radiation syndrome

syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours; "he was suffering from radiation" ;

radiation therapy

(medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance ;

radiator

a mechanism consisting of a metal honeycomb through which hot fluids circulate; heat is transferred from the fluid through the honeycomb to the airstream that is created either by the motion of the vehicle or by a fan ; heater consisting of a series of pipes for circulating steam or hot water to heat rooms or buildings ; any object that radiates energy ;

radiator cap

cap on the opening in the top of a radiator through which a coolant liquid can be added ;

radiator grille

grating that admits cooling air to car's radiator ;