CNSI
| 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) |