The Collaborative International Dictionary of English v.0.48:

Ne exeat \Ne` ex"e*at\ [L. ne exeat regno let him not go out of
   the kingdom.] (Law)
   A writ to restrain a person from leaving the country, or the
   jurisdiction of the court. The writ was originally applicable
   to purposes of state, but is now an ordinary process of
   courts of equity, resorted to for the purpose of obtaining
   bail, or security to abide a decree. --Kent.
   [1913 Webster]