Line of sight

What is Line of sight?

Line of sight definition and meaning on Dictionary terms:
noun

Also called line of sighting. an imaginary straight line running through the aligned sights of a firearm, surveying equipment, etc.
Astronomy. an imaginary line from an observer to a celestial body, coincident with the path traveled by light rays receivedfrom the body.
Radio. a straight line connecting two points sufficiently high and near one another so that the line is entirely above the surface of the earth.
Ophthalmology. line of vision.