SYI
| Acronym | Definition |
|---|---|
| SYI | Sell Your Item |
| SYI | Seijiro Yazawa Iwai (Toshiba distributor) |
| SYI | Summer Youth Institute (various organizations) |
| SYI | Shanxi Yuansheng Industrial Co. Ltd. (China) |
| SYI | stealing your info |
| SYI | Systemic Yeast Infection (canine disease) |
| SYI | Share Your Ignorance |
| SYI | Sustainable Yield Index (agriculture; India) |