| Acronym | Definition |
|---|
| SEIN | Stichting Epilepsie Instellingen Nederland (Dutch: Epilepsy Institutes Foundation Netherlands) |
| SEIN | Sistema Eléctrico Interconectado Nacional (Perú) |
| SEIN | State Employment Identification Number |
| SEIN | Social and Environmental Impact Network (Aspen Institute Center for Business Education; now Corporate Governance Network) |
| SEIN | Swiss Export Information Network (Switzerland) |
| SEIN | Societal and Ethical Issues in Nanotechnology |
| SEIN | Secondary Education in Nigeria (World Bank study) |
| SEIN | Support Equipment Item Number |