Definition/Meaning  Word/Phrase 
measure of the rate of decrease in the intensity of electromagnetic radiation (as light) as it passes through a given substance; the fraction of incident radiant energy absorbed per unit mass or thickness of an absorber 
absorptance
,
absorption coefficient
,
coefficient of absorption

(physics) the property of a body that determines the fraction of the incident radiation or sound flux absorbed or absorbable by the body 
absorption factor
,
absorptivity

conductor having low resistance in parallel with another device to divert a fraction of the current 
bypass
,
electrical shunt
,
shunt

fraction of radiant energy that is reflected from a surface 
coefficient of reflection
,
reflectance
,
reflection factor
,
reflectivity

fraction with fractions in the numerator or denominator 
complex fraction
,
compound fraction

fraction whose numerator is an integer and whose denominator is an integer plus a fraction whose numerator is an integer and whose denominator is an integer plus a fraction and so on 
continued fraction

dot at the left of a decimal fraction 
decimal point
,
percentage point

proper fraction whose denominator is a power of 10 
decimal
,
decimal fraction

divisor of a fraction 
denominator

fraction, number below line in 
denominator
,
divisor

refund of some fraction of the amount paid 
discount
,
rebate

fraction, number above line in 
dividend
,
numerator

fraction, line in 
dividing line

monetary unit that is valued at a fraction (usually one hundredth) of the basic monetary unit 
fractional monetary unit
,
subunit

water pump that uses the kinetic energy of flowing water to force a small fraction of that water to a reservoir at a higher level 
hydraulic pump
,
hydraulic ram

fraction whose numerator is larger than the denominator 
improper fraction

dividend of a fraction 
numerator

resistors connected in series across a voltage source; used to obtain a desired fraction of the voltage 
potential divider
,
voltage divider

fraction with a numerator smaller than the denominator 
proper fraction

number that is integer or quotient of integers, whole number or fraction 
rational number
