Webster's Revised Unabridged Dictionary · 1913

Proportional

Proportional , adjective

[Latin proportionalis: compare French proportionnel.]

1.
Having a due proportion, or comparative relation; being in suitable proportion or degree; as, the parts of an edifice are proportional. — Milton
2.
Relating to, or securing, proportion. — Hutton
3.
(Mathematics) Constituting a proportion; having the same, or a constant, ratio; as, proportional quantities; momentum is proportional to quantity of matter.
Collocations (3)
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 or scales, compasses, dividers (Draughting) , instruments used in making copies of drawings, or drawings of objects, on an enlarged or reduced scale.

Proportional , noun

1.
(Mathematics) Any number or quantity in a proportion; as, a mean proportional.
2.
(Chemistry) The combining weight or equivalent of an element. [Obsolete]