pertaining to fractions; comprising a part or the parts of a unit; constituting a fraction

fractional numbers.

comparatively small; inconsiderable or insignificant

The profit on the deal was fractional.

Chemistry . of or noting a process, as distillation, crystallization, or oxidation, by which the component substances of a mixture are separated according to differences in certain of their properties, as boiling point, critical temperature, or solubility.