Source : Webster's Revised Unabridged Dictionary (1913)

Muster \Mus"ter\, v. t. [imp. & p. p. {Mustered}; p. pr. & vb.
   n. {Mustering}.] [OE. mustren, prop., to show, OF. mostrer,
   mustrer, moustrer, monstrer, F. montrer, fr. L. monstrare to
   show. See {Monster}.]
   1. To collect and display; to assemble, as troops for parade,
      inspection, exercise, or the like. --Spenser.

   2. Hence: To summon together; to enroll in service; to get
      together. ``Mustering all its force.'' --Cowper.

            All the gay feathers he could muster. --L'Estrange.

   {To muster troops into service} (Mil.), to inspect and enter
      troops on the muster roll of the army.

   {To muster troops out of service} (Mil.), to register them
      for final payment and discharge.

   {To muster up}, to gather up; to succeed in obtaining; to
      obtain with some effort or difficulty.

            One of those who can muster up sufficient
            sprightliness to engage in a game of forfeits.
                                                  --Hazlitt.