Source : Webster's Revised Unabridged Dictionary (1913)

Proportionality \Pro*por`tion*al"i*ty\, n. [Cf. F.
   proportionnalit['e].]
   The state of being in proportion. --Coleridge.

Source : WordNet®

proportionality
     n : the quotient obtained when the magnitude of a part is
         divided by the magnitude of the whole [syn: {proportion}]