The Collaborative International Dictionary of English v.0.48:

Extraterritoriality \Ex`tra*ter`ri*to`ri*al"i*ty\, n.
   The state of being beyond the limits of a particular
   territory; esp. (Internat. Law), A fiction by which a public
   minister, though actually in a foreign country, is supposed
   still to remain within the territory of his own sovereign or
   nation. --Wheaton.
   [1913 Webster]