Source : Webster's Revised Unabridged Dictionary (1913)

Mass \Mass\, v. i. [imp. & p. p. {Massed}; p. pr. & vb. n.
   {Massing}.]
   To celebrate Mass. [Obs.] --Hooker.

Source : WordNet®

massed
     adj : brought together into a group or crowd; "the accumulated
           letters in my office" [syn: {accumulated}, {amassed}, {assembled},
            {collected}, {congregate}]