| Acronym | Definition |
|---|
| I | One (Roman numeral) |
| I | Interest |
| I | Incomplete (school) |
| I | Italic |
| I | Information |
| I | Internet |
| I | Current (electronics) |
| I | International |
| I | Input |
| I | Island |
| I | Industry |
| I | Included (lowest quality of diamond) |
| I | Investment (economics) |
| I | India |
| I | Italy (International Auto Identification) |
| I | Interactive |
| I | Independent |
| I | Immediate (precedence level) |
| I | In Phase |
| I | Industries |
| I | Inventory (TOC) |
| I | Indoor |
| I | Instructional |
| I | Instructor (Boy Scouts of America) |
| I | Inspection |
| I | Incorporated |
| I | Intermediate |
| I | Informative |
| I | Interstate (highway) |
| I | Immigration |
| I | Injection |
| I | Inclination (astronomy) |
| I | Indicator |
| I | Imagery (often associated with satellite remote sensing) |
| I | Increment (Bit) |
| I | Inertial |
| I | Iodine |
| I | Isoleucine (amino acid) |
| I | Interpolated |
| I | Interlaced |
| I | Interlacing |
| I | Intercot (Disney) |
| I | Ionisierungsenergie (German) |
| I | Intensitie (French: Electrical Current) |
| I | Federal Reserve Bank of Minneapolis, Minnesota (designates original point of circulation of a dollar bill) |
| I | Imaginary number; the square root of -1 |
| I | Intrapictures |