SIS

The initials SIS may stand for:

1. Swedish Standards Institute (earlier named Standardiseringskommissionen i Sverige).
2. Schengen Information System.
3. Secret Intelligence Service (MI6).
4. Security Intelligence Service (espionage New Zealand style)
5. Signals Intelligence Service. This United States Army group, led by William F. Friedman, broke the Japanese Foreign Office cypher called Purple. It eventually became a part of the NSA.

Compare Sis - a settlement in Turkey.