Source : Webster's Revised Unabridged Dictionary (1913)

Commodiousness \Com*mo"di*ous*ness\, n.
   State of being commodious; suitableness for its purpose;
   convenience; roominess.

         Of cities, the greatness and riches increase according
         to the commodiousness of their situation. --Sir W.
                                                  Temple.

         The commodiousness of the harbor.        --Johnson.

Source : WordNet®

commodiousness
     n : spatial largeness (especially inside a building) [syn: {capaciousness},
          {roominess}, {spaciousness}]