The Collaborative International Dictionary of English v.0.48:

Pospolite \Pos"po*lite\, n. [Pol. pospolite ruszenie a general
   summons to arms, an arriere-ban; pospolity general + ruszenie
   a stirring.]
   A kind of militia in Poland, consisting of the gentry, which,
   in case of invasion, was summoned to the defense of the
   country.
   [1913 Webster]