ratio

/ˈreɪʃioʊ/

/ˈreɪʃiəʊ/

Other forms: ratios

A ratio is the relationship in quantity or degree between two things: “The ratio of men to women on the construction site was ten to one.” This means there were ten men present and one woman.

Use the word ratio when you want to make a comparison between two things. A ratio basically expresses a proportion. Often used in mathematics, the word ratio has many real world uses as well. This word is useful for everything from making salad dressing (an oil-to-vinegar ratio of three to one) to selecting a school for a child (consider the student-to-teacher ratio when making your decision).

Definitions of ratio

1. noun

   the relation between things (or parts of things) with respect to their comparative quantity, magnitude, or degree
   synonyms: proportion

   type of:

   magnitude relation, quantitative relation

   a relation between magnitudes
2. noun

   the relative magnitudes of two quantities (usually expressed as a quotient)
   types:

   gross margin, margin of profit, profit margin

   the ratio gross profits divided by net sales

   abundance

   (chemistry) the ratio of the total mass of an element in the earth's crust to the total mass of the earth's crust; expressed as a percentage or in parts per million

   abundance

   (physics) the ratio of the number of atoms of a specific isotope of an element to the total number of isotopes present

   albedo, reflective power

   the ratio of reflected to incident light

   aspect ratio

   the ratio of the width to the height of a tv picture

   average

   (sports) the ratio of successful performances to opportunities

   breadth index, cephalic index, cranial index

   ratio (in percent) of the maximum breadth to the maximum length of a skull

   efficiency

   the ratio of the output to the input of any system

   facial index

   the ratio (in percent) of the maximum width to the maximum height of the face

   f number, focal ratio, speed, stop number

   the ratio of the focal length to the diameter of a (camera) lens system

   frequency, relative frequency

   the ratio of the number of observations in a statistical category to the total number of observations

   haematocrit, hematocrit, packed cell volume

   the ratio of the volume occupied by packed red blood cells to the volume of the whole blood as measured by a hematocrit

   I.Q., IQ, intelligence quotient

   a measure of a person's intelligence as indicated by an intelligence test; the ratio of a person's mental age to their chronological age (multiplied by 100)

   load factor

   (aeronautics) the ratio of an external load to the weight of the aircraft (measured in g)

   loss ratio

   the ratio of the annual claims paid by an insurance company to the premiums received

   Mach number

   the ratio of the speed of a moving body to the speed of sound

   magnification

   the ratio of the size of an image to the size of the object

   mechanical advantage

   the ratio of the force exerted by a machine to the force applied to it

   fuel consumption rate, gas mileage, gasoline mileage, mileage

   the ratio of the number of miles traveled to the number of gallons of gasoline burned

   betting odds, odds

   the ratio by which one better's wager is greater than that of another

   magnitude, order of magnitude

   a number assigned to the ratio of two quantities; two quantities are of the same order of magnitude if one is less than 10 times as large as the other; the number of magnitudes that the quantities differ is specified to within a power of 10

   output-to-input ratio

   the output power of a transducer divided by the input power

   prevalence

   (epidemiology) the ratio (for a given time period) of the number of occurrences of a disease or event to the number of units at risk in the population

   P/E ratio, price-to-earnings ratio

   (stock market) the price of a stock divided by its earnings

   productivity

   (economics) the ratio of the quantity and quality of units produced to the labor per unit of time

   proportionality

   a ratio of two quantities that is constant

   quotient

   the ratio of two quantities to be divided

   index of refraction, refractive index

   the ratio of the velocity of light in a vacuum to that in a medium

   relative humidity

   the ratio of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature; expressed as a percentage

   respiratory quotient

   the ratio of the volume of carbon dioxide expired to the volume of oxygen consumed by an organism or cell in a given period of time

   factor of safety, safety factor

   the ratio of the breaking stress of a structure to the estimated maximum stress in ordinary use

   S/N, signal-to-noise, signal-to-noise ratio, signal/noise, signal/noise ratio

   the ratio of signal intensity to noise intensity

   stoichiometry

   (chemistry) the relation between the quantities of substances that take part in a reaction or form a compound (typically a ratio of whole integers)

   time constant

   the ratio of the inductance of a circuit in henries to its resistance in ohms

   employee turnover, turnover, turnover rate

   the ratio of the number of workers that had to be replaced in a given time period to the average number of workers

   loading

   the ratio of the gross weight of an airplane to some factor determining its lift

   eccentricity

   (geometry) a ratio describing the shape of a conic section; the ratio of the distance between the foci to the length of the major axis

   proportion

   the quotient obtained when the magnitude of a part is divided by the magnitude of the whole

   commensurateness, correspondence, proportionateness

   the relation of corresponding in degree or size or amount

   batting average, hitting average

   (baseball) a measure of a batter's performance; the number of base hits divided by the number of official times at bat

   fielding average

   (baseball) a measure of a fielder's performance; the number of assists and putouts divided by the number of chances

   figure of merit

   a numerical expression representing the efficiency of a given system, material, or procedure

   adult intelligence

   the average IQ of the adults in a given population

   borderline intelligence

   the minimal IQ required for someone to function normally and independently in the world (without some form of institutional assistance)

   power loading

   the ratio of the weight of an airplane to its engine power

   span loading

   the ratio of the weight of an airplane to its wingspan

   wing loading

   the ratio of the weight of an airplane to its wing area

   incidence, relative incidence

   the relative frequency of occurrence of something

   type of:

   magnitude relation, quantitative relation

   a relation between magnitudes