Source : Webster's Revised Unabridged Dictionary (1913)

Replaceability \Re*place`a*bil"i*ty\ (-?-b?l"?-t?), n.
   The quality, state, or degree of being replaceable.

Source : WordNet®

replaceability
     n : exchangeability by virtue of being replaceable [syn: {substitutability},
          {commutability}]