a ratio of algebraic quantities similarly expressed.

Chemistry. (in a volatile mixture) a component whose range of boiling point temperatures allows it to be separated from other components by fractionation.

a part as distinct from the whole of anything; portion or section: The meeting started with a fraction of us present.

a very small part or segment of anything; minute portion: Only a fraction of the work was completed on time.

a very small amount; a little bit: It was only a fraction away from completion.

a piece broken off; fragment or bit.

the act of breaking.

Ecclesiastical. (in a Eucharistic service) the breaking of the Host.

verb (used with or without object)

to divide or break into fractions, sections, factions, etc.: Dissension threatens to fraction the powerful union.

Origin of fraction

1350–1400;Middle Englishfraccioun < Late Latinfrāctiōn- (stem of frāctiō) a breaking (in pieces), equivalent to Latinfrāct(us) (past participle of frangere to break) + -iōn--ion

late 14c., originally in the mathematical sense, from Anglo-French fraccioun (Old French fraccion, 12c., "breaking") and directly from Late Latin fractionem (nominative fractio) "a breaking," especially into pieces, noun of action from past participle stem of Latin frangere "to break," from PIE root *bhreg- "to break" (cf. Sanskrit (giri)-bhraj "breaking-forth (out of the mountains);" Gothic brikan, Old English brecan "to break;" Lithuanian brasketi "crash, crack;" Old Irish braigim "break" wind). Meaning "a breaking or dividing" is from early 15c.; sense of "broken off piece, fragment," is from c.1600.

A number that compares part of an object or a set with the whole, especially the quotient of two whole numbers written in the form ab. The fraction 12, which means 1 divided by 2, can represent such things as 10 pencils out of a box of 20, or 50 cents out of a dollar. See also decimal fractionimproper fractionproper fraction.

A mathematical expression representing the division of one whole number by another. Usually written as two numbers separated by a horizontal or diagonal line, fractions are also used to indicate a part of a whole number or a ratio between two numbers. Fractions may have a value of less than one, as with 1/2, or equal to one, as with 2/2, or more than one, as with 3/2. The top number of a fraction is the numerator and the bottom number is the denominator.