| Acronym | Definition |
|---|
| CASU | Casualty |
| CASU | Conseiller d'Administration Scolaire et Universitaire (French: School and University Administration Advisor) |
| CASU | Cooperative Administrative Support Unit (GSA) |
| CASU | Carrier Aircraft Service Unit (USN) |
| CASU | Cambridge Astronomical Survey Unit (UK) |
| CASU | Combat Aircraft Service Unit (US DoD) |
| CASU | Client Advisory Services Unit (Oregon Health Plan) |
| CASU | Centrale d'Appels Sanitaires Urgents (Geneva, Switzerland medical emergencies call center) |
| CASU | College of Arts Student Union (University of Guelph, Ontario, Canada) |