| Abbreviation | Definition |
|---|---|
| LK | Leak |
| LK | Lock |
| LL | Launch and Landing |
| LL | Launch Left |
| LL | Lever Lock |
| LL | Long Lead |
| LL | Long Line |
| LL | Low Level |
| LL | Lower Left |
| LL | Lower Limit |
| L-L | Line-to-Line |
| LLCF | Launch and Landing Computational Facilities |
| LLI | Limited Life Item |
| LLIL | Long Leadtime Items List |
| LLM | Lunar Landing Module |
| LLOS | Landmark Line-of-Sight |
| LLP | Launch and Landing Project |
| LLPO | Launch and Landing Project Office |
| LLPO | Lunar Lander Project Office (US NASA) |
| LLS | Launch and Landing Site |