The Collaborative International Dictionary of English v.0.48:

Pacha \Pa*cha"\, n. [F.]
   A civil or military authority in Turkey or Egypt; same as
   Pasha.
   [1913 Webster + WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Pasha \Pa*sha"\, n. [Turk. p[=a]sh[=a], b[=a]sh[=a]; cf. Per.
   b[=a]sh[=a], b[=a]dsh[=a]h; perh. a corruption of Per.
   p[=a]dish[=a]h. Cf. Bashaw, Padishah, Shah.]
   An honorary title given to officers of high rank in Turkey,
   as to governers of provinces, military commanders, etc. The
   earlier form was bashaw. [Written also pacha.]
   [1913 Webster]

   Note: There are three classes of pashas, whose rank is
         distinguished by the number of the horsetails borne on
         their standards, being one, two, or three, a pasha of
         three tails being the highest.
         [1913 Webster]

WordNet (r) 3.0 (2006):

pacha
    n 1: a civil or military authority in Turkey or Egypt [syn:
         pasha, pacha]