The Collaborative International Dictionary of English v.0.48:

Uhlan \Uh"lan\, n. [G. uhlan, Pol. ulan, hulan, from Turk.
   ogl[=a]n a youth, lad; of Tartar origin.] [Written also
   ulan, and formerly hulan.]
   1. One of a certain description of militia among the Tartars.
      [1913 Webster]

   2. (Mil.) One of a kind of light cavalry of Tartaric origin,
      first introduced into European armies in Poland. They are
      armed with lances, pistols, and sabers, and are employed
      chiefly as skirmishers.
      [1913 Webster]