fraction

Pluralfractions

Formsfractions, fractioning, fractioned

1. 1
   nouncountable

   A part of a whole, especially when it is comparatively small.

   Only a fraction of the applicants were invited to interview.

   A large fraction of the budget went toward emergency repairs.

   Similarportion, part, proportion, share, percentage

   Oppositewhole, entirety

   Note

   Behind every meaning of the word is a breaking: Middle English fraccioun, through French from Latin fractio, from frangere, "to break." A part of a whole is, at root, a piece broken off it. It usually appears as "a fraction of," and it leans small: "only a fraction" implies very little. When the share is big, say so outright, as in "a large fraction of the budget."

2. 2
   nouncountable

   A ratio of two numbers, a numerator and a denominator, usually written one above the other separated by a horizontal bar, or side by side separated by a slash.

   To add two fractions, first give them a common denominator.

   The fraction 7/8 lies just short of a whole.

   Note

   Arithmetic names every part precisely. The number on top is the numerator, the one below is the denominator, and the horizontal bar between them is the vinculum. Written on one line, a slanted solidus does the same job. A proper fraction is smaller than one, and an improper one is equal to or greater than one. Gas-station signs still post a tenth of a cent this way: $3.59⁹⁄₁₀.

3. 3
   nouncountable

   A small amount or degree of something.

   She hesitated for a fraction of a second before answering.

   The new model is only a fraction heavier than the old one.

   Similarbit, tad, touch, shade, hair

   Note

   Used adverbially, "a fraction" scales down a comparison: a shot swerves a fraction wide, and a model is a fraction heavier. Chris Bevan's 2011 BBC match report has a shot go "a fraction wide." The American novelist Winston Churchill's The Celebrity (1897) stretches the word playfully when Farrar "smiled his wonted fraction," a smile so slight it barely counts as one.

4. 4
   verbtransitive

   To divide or break something into separate parts.

   The engineers fraction the signal into several frequency bands.

   Accountants fraction the total cost across many departments.

   Similardivide, split, partition, segment, separate

   Oppositecombine, merge, unite

5. 5
   nouncountable

   In chemistry, any of the portions into which a mixture is split by fractionation, such as gasoline from crude oil.

   Crude oil is separated into fractions such as gasoline and kerosene.

   Each fraction was collected at a different boiling point.

   Similarcut, component, distillate

   Note

   In the laboratory or refinery, a portion is defined by how it was collected. A distillation or chromatographic run splits a mixture by one physical property, such as boiling point or molecular size. Each portion holds compounds within a narrow range of that property. The process is fractionation, and the verb is fractionate, or the shorter verb.

6. 6
   verbtransitive

   To separate a mixture into distinct components by fractionation.

   Technicians fraction the plasma to isolate the clotting factors.

   The plant fractions natural gas into methane, ethane, and propane.

   Similarseparate, fractionate

7. 7
   noun

   In a Eucharistic service, the breaking of the consecrated host.

   The liturgy reaches a solemn point at the fraction, when the host is broken.

   At the fraction the celebrant divides the host into pieces for distribution.

   Note

   A liturgical term that keeps the Latin "breaking" intact. The celebrant breaks the consecrated bread after the canon and before communion. This divides it for the communicants and recalls the breaking of Christ's body. Jeremy Taylor, writing before 1668, speaks of "the fraction and distribution" of the bread. In this use the word nearly always takes the definite article: the fraction.

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