Source : Webster's Revised Unabridged Dictionary (1913)

Trainband \Train"band`\, n.; pl. {Trainbands}.
   A band or company of an organized military force instituted
   by James I. and dissolved by Charles II.; -- afterwards
   applied to the London militia. [Eng.]

         He felt that, without some better protection than that
         of the trainbands and Beefeaters, his palace and person
         would hardly be secure.                  --Macaulay.

         A trainband captain eke was he Of famous London town.
                                                  --Cowper.

Source : WordNet®

trainband
     n : a company of militia in England or America from the 16th
         century to the 18th century