Source : Webster's Revised Unabridged Dictionary (1913)

Modality \Mo*dal"i*ty\, n. [Cf. F. modalit['e].]
   1. The quality or state of being modal.

   2. (Logic & Metaph.) A modal relation or quality; a mode or
      point of view under which an object presents itself to the
      mind. According to Kant, the quality of propositions, as
      assertory, problematical, or apodeictic.

Source : WordNet®

modality
     n 1: a classification of propositions on the basis of whether
          they claim necessity or possibility or impossibility
          [syn: {mode}]
     2: verb inflections that express how the action or state is
        conceived by the speaker [syn: {mood}, {mode}]
     3: a particular sense [syn: {sense modality}, {sensory system}]
     4: a method of therapy that involves physical or electrical
        therapeutic treatment