Mathematics .

a number usually expressed in the form a/b.

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.

to divide or break into fractions, sections, factions, etc.

Dissension threatens to fraction the powerful union.

noun

entirety , total , whole

noun

bite , chunk , cut , division , end , fragment , half , piece , portion , section , share , slicenotes:a faction is a group of people forming a cohesive , usually contentious , minority from within a larger group; a fraction is a small part or item of something forming a piece of a whole , bit , part , partial , quotient , ratio , segment , slice , subdivisionnotes:a faction is a group of people forming a cohesive , break , breaking , component , little , modicum , moiety , proportion , quanta , quantum