Aircraft instruments Reference Libraries
A radar altimeter measures altitude above the terrain beneath an aircraft as opposed to a barometric altimeter which provides the distance above a pre-determined datum, usually sea level. Radar is the underpinning principle of the system. Radio waves that are reflected back from the ground are timed in order to calculate speed, distance, and time which are related to the each other and can be...
- An evil spirit; a devil.
- A nightmare.
- In astrology, the twelfth house of a scheme or figure of the heavens: so called from its signifying dreadful things, such as secret enemies, great losses, imprisonment, etc.