line of sight
- The line extending from a telescope or other long-distance sighting device, along which distant objects can be viewed. See also sight line.
- A direct and unobstructed path between a transmitting device and a receiving or reflecting device. For instance, such a path between a transmitting antenna and a receiving antenna, or between a radar signal and a scanned object.
- A straight line between an eye or lens and that which is observed.
- noun a straight path, not passing over the horizon, between a transmitting and receiving aerial.