a. 1. Of or pertaining to fractions or a fraction; constituting a fraction; as, fractional numbers. [ 1913 Webster ]
2. Relatively small; inconsiderable; insignificant; as, a fractional part of the population. [ 1913 Webster ]
Fractional crystallization (Chem.), a process of gradual and approximate purification and separation, by means of repeated solution and crystallization therefrom. -- Fractional currency, small coin, or paper notes, in circulation, of less value than the monetary unit. -- Fractional distillation (Chem.), a process of distillation so conducted that a mixture of liquids, differing considerably from each other in their boiling points, can be separated into its constituents. [ 1913 Webster ]