The Collaborative International Dictionary of English v.0.48:

Commodious \Com*mo"di*ous\, a. [LL. commodiosus, fr. L. commodum
   convenience, fr. commodus. See Commode.]
   Adapted to its use or purpose, or to wants and necessities;
   serviceable; spacious and convenient; roomy and comfortable;
   as, a commodious house. "A commodious drab." --Shak.
   "Commodious gold." --Pope.
   [1913 Webster]

         The haven was not commodious to winter in. --Acts
                                                  xxvii. 12.

   Syn: Convenient; suitable; fit; proper; advantageous;
        serviceable; useful; spacious; comfortable.
        [1913 Webster]

WordNet (r) 3.0 (2006):

commodious
    adj 1: large and roomy (`convenient' is archaic in this sense);
           "a commodious harbor"; "a commodious building suitable
           for conventions" [syn: commodious, convenient] [ant:
           incommodious]