| Acronym | Definition |
|---|
| ONSA➣Ohio Nursing Students' Association |
| ONSA➣Oklahoma Nursing Student Association |
| ONSA➣Office of the National Science Advisor (Canada) |
| ONSA➣Organization for Nucleotide Sequencing and Analysis |
| ONSA➣Oregon Neighborhood Store Association |
| ONSA➣Operasionele Navorsingsvereniging Van Suid-Afrika (Afrikaans: Operations Research Society of South Africa) |
| ONSA➣Office of the National Security Adviser (various nations) |