| Acronym | Definition |
|---|
| I&I | Industrial and Institutional |
| I&I | Inflow & Infiltration |
| I&I | Injury & Illness |
| I&I | Inspector & Instructor |
| I&I | Interoperability and Integration |
| I&I | Industrial and Institutional cleaning |
| I&I | Installation and Integration |
| I&I | Inflammation and Immunity (medical disorders) |
| I&I | Impact & Implementation |
| I&I | Inventions & Innovations (US DOE) |
| I&I | Intercourse and Intoxication (GI update of R&R) |
| I&I | Items and Instructions |
| I&I | Interworking and Interoperability |
| I&I | Inquiries & Investigations |
| I&I | Interoperability & Interchangeability |
| I&I | Incremental & Iterative |