HALO (plural HALOs)
- (aviation, parachuting) High altitude, low opening. — a type of skydiving, where you leave the launch platform from a high altitude, and open the parachute at a very low altitude.
- When you have enough experience, you can do a HALO jump.
- Hazardous area life-support organisation.
- High altitude, low orbiting. Used in reference to certain aviation crafts. For example, weather balloons, when at maximum altitude are considered HALOs.