| Acronym | Definition |
|---|
| NHSI➣National High School Invitational (basketball event) |
| NHSI➣National High School Institute (est. 1931; Northwestern University; Evanston, IL) |
| NHSI➣National Health Services, Inc. (California) |
| NHSI➣National Health Surveillance Infostructure (Health Canada) |
| NHSI➣National Healthcare Solutions, Inc. |
| NHSI➣Normal-to-High Salt Intake (nutritional science) |