| 1. | pertaining to fractions; comprising a part or the parts of a unit; constituting a fraction: fractional numbers. |
| 2. | comparatively small; inconsiderable or insignificant: The profit on the deal was fractional. |
| 3. | 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. |