speed (redirected from speed of light)

speed

Etymology: AS, spedan, to hasten

1 the rate of change of position with time. Compare velocity.

2 See amphetamines.

3 a reciprocal of the amount of radiation used to produce an image with various components of an x-ray imaging system, such as screens, film, and image intensifiers. There is often a tradeoff between radiation dose to the patient and the overall image quality. Thus a system using little radiation is "fast," whereas one requiring more radiation is "slow."

4 the amount of exposure of film to light or x-rays needed to produce a desired image. X-ray film speed usually is indicated as the reciprocal of the exposure in roentgens necessary to produce a density of 1 above the base and fog levels. See also fogged film fault.

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speed,

n the relative rapidity of action; rate of motion.

speed, film,

n See film speed.

speed, high,

n a relatively great rapidity of motion. In cavity preparations, rotary instruments are classified according to the number of revolutions per minute (rpm) made by the cutting tool. Designation of each speed range presently varies. In general, conventional speed is 10,000 to 60,000 rpm, high speed is 60,000 to 100,000 rpm, and ultrahigh speed is more than 100,000 rpm. May also be used to describe an evacuation system.

speed of light,

n a speed of 186,300 miles/sec.

speed of radiation,

n See radiation, speed of.

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SPEED

Cardiology A clinical trial–Strategies for Patency Enhancement in the Emergency Department

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speed

Drug slang A street synonym for amphetamine, which may also refer to methamphetamine and crack