The Collaborative International Dictionary of English v.0.48:

Yager \Ya"ger\ (?; 277), n. [G. j[aum]ger a hunter, from jagen
   to chase, hunt.] (Mil.)
   In the German army, one belonging to a body of light infantry
   armed with rifles, resembling the chasseur of the French
   army. [Written also jager.]
   [1913 Webster]