| Acronym | Definition |
|---|
| LEF | Life Extension Foundation |
| LEF | Leading Edge Forum (CSC) |
| LEF | Light Emmitting Film |
| LEF | Local Event Flag |
| LEF | Luquillo Experimental Forest (USDA) |
| LEF | Library Exchange Format (Cadence Design Systems) |
| LEF | Local Education Funds |
| LEF | Literacy Empowerment Foundation |
| LEF | Leading Edge Flap |
| LEF | Load Equivalency Factor (civil engineering) |
| LEF | Lymphoid Enhancer-Binding Factor |
| LEF | Linear Electric Field |
| LEF | Life Energy Foundation (Verbank, NY) |
| LEF | Link Encryption Family |
| LEF | Long Edge First (printer paper handling) |
| LEF | Lebanese Environment Forum |
| LEF | Lake Erie, Franklin, and Clarion (railroad) |
| LEF | Label-Encodings File |
| LEF | Laser Excited Fluorescence |
| LEF | Lao Evangelical Fellowship |
| LEF | Load Enhancement Factor (structural testing) |
| LEF | Loyalty Enforcement Facilitator (Left Behind book series) |
| LEF | Large-Amplitude Electric Field Fluctuations |
| LEF | Laboratoire d'Expérimentation des Feux (French: Fire Experimentation Laboratory) |