What does "proportional" mean?

Additional senses

1. 2.(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.
2. 3.(Math.) Any number or quantity in a proportion; as, a mean proportional.
3. 4.(Chem.) The combining weight or equivalent of an element. [Obs.]