Source : Webster's Revised Unabridged Dictionary (1913)

Protectorate \Pro*tect"or*ate\, n. [Cf. F. protectorat.]
   1. Government by a protector; -- applied especially to the
      government of England by Oliver Cromwell.

   2. The authority assumed by a superior power over an inferior
      or a dependent one, whereby the former protects the latter
      from invasion and shares in the management of its affairs.

Source : WordNet®

protectorate
     n : a state or territory partly controlled by (but not a
         possession of) a stronger state but autonomous in
         internal affairs; protectorates are established by treaty
         [syn: {associated state}]