Pro·por·tion·al a.
1. Having a due proportion, or comparative relation; being in suitable proportion or degree; as, the parts of an edifice are proportional.
2. Relating to, or securing, proportion.
3. Math. Constituting a proportion; having the same, or a constant, ratio; as, proportional quantities; momentum is proportional to quantity of matter.
Proportional logarithms, logistic logarithms. See under Logistic.
Proportional scale, a scale on which are marked parts proportional to the logarithms of the natural numbers; a logarithmic scale.
Proportional scales, compasses, dividers, etc. Draughting, instruments used in making copies of drawings, or drawings of objects, on an enlarged or reduced scale.