Constituting or comprising a part or fraction of a possible whole or entirety.

Roget 51: fractional, fragmentary; sectional, aliquot; divided etc. v.; in compartments, multifid^†; disconnected; partial.   

Roget 84: numeral, complementary, divisible, aliquot, reciprocal, prime, relatively prime, fractional, decimal, figurate^†, incommensurable.    proportional, exponential, logarithmic, logometric^†, differential, fluxional^†, integral, totitive^†.    positive, negative; rational, irrational; surd, radical, real; complex, imaginary; finite; infinite; impossible.    ... show more

Roget 100a: fractional, fragmentary, inconsiderable, negligible, infinitesimal.   

Dutch: fractioneel
Polish: ułamkowy