What is "extraterritoriality"

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.

also extra-territoriality, "privilege customarily extended to diplomats abroad of enjoying such rights and privileges as belong to them at home," 1803, from extraterritorial (from extra- + territorial) + -ity. Same as Exterritoriality.

n. (context legal English) immunity from the local laws of a certain area, especially due to diplomatic negotiation.

Extraterritoriality is the state of being exempted from the jurisdiction of local law, usually as the result of diplomatic negotiations. Historically, this applied to individuals. Extraterritoriality can also be applied to physical places, such as foreign embassies, military bases of foreign countries, or offices of the United Nations. The three most common cases recognized today internationally relate to the persons and belongings of foreign heads of state, the persons and belongings of ambassadors and other diplomats, and ships in foreign waters.

Extraterritoriality is often extended to friendly or allied militaries, particularly for the purposes of allowing that military to simply pass through one's territory.

It is distinguished from personal jurisdiction in the sense that extraterritoriality operates to the prejudice of local jurisdiction.