| Acronym | Definition |
|---|
| CNSI➣California NanoSystems Institute (University of California at Santa Barbara) |
| CNSI➣Club Nautico San Isidro (Spanish: Nautical Club San Isidro; Argentina) |
| CNSI➣Client Network Services, Inc. (Rockville, MD) |
| CNSI➣Classified National Security Information (US) |
| CNSI➣Confidential National Security Information (US) |
| CNSI➣Committee on the Safety of Nuclear Installations |
| CNSI➣Central Nervous System Infection (illness) |