| Acronym | Definition |
|---|
| OSEC➣Office Suisse d'Expansion Commerciale (French: Swiss Office for Commercial Expansion; now Swiss Agency for Foreign Trade Promotion) |
| OSEC➣Ocean Systems Engineering Corporation |
| OSEC➣On-Site-Electrolytic-Chlorination (Wallace & Tiernan) |
| OSEC➣Open Security Evaluation Criteria |
| OSEC➣Office of Sustainable Ecosystems and Communities (EPA) |
| OSEC➣Observatório de Segurança das Estradas e Cidades (Portugal) |
| OSEC➣Office Systems Education & Counseling |
| OSEC➣Ovarian Surface Epithelial Cell (biology) |