The Collaborative International Dictionary of English v.0.48:

Artesian \Ar*te"sian\, a. [F. art['e]sien, fr. Artois in France,
   where many such wells have been made since the middle of the
   last century.]
   Of or pertaining to Artois (anciently called Artesium), in
   France.
   [1913 Webster]

   Artesian wells, wells made by boring into the earth till
      the instrument reaches water, which, from internal
      pressure, flows spontaneously like a fountain. They are
      usually of small diameter and often of great depth.
      [1913 Webster]