| Obstacle limitation surface | Obstacle Limitation Surfaces (OLS) according to Annex 14 |
| AOC surface | Take-off flight path area (AOC-surface) for IFR-Operations |
| VASIS protection surface | Obstacle protection surface for VASIS |
| CNS protection surface | Protection surface for CNS infrastructure |
| PANS-OPS surface | Obstacle Assessment (OAS), Identification (OIS) or Clearance Surface (OCS) according ICAO Doc 8168 Volume II |
| Obstacle coverage area | Geographic area for which obstacle data is provided |
| Terrain coverage area | Geographic area for which terrain data is provided |
| Obstacle | All fixed (whether temporary or permanent) and mobile obstacles or parts thereof, |