line of sight

[lahyn uhv sahyt]

noun

1. Also called line of sighting. an imaginary straight line running through the aligned sights of a firearm, surveying equipment, etc.

2. Astronomy.,  an imaginary line from an observer to a celestial body, coincident with the path traveled by light rays receivedfrom the body.

3. 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.

4. Ophthalmology.,  line of vision.

5. sightline.

line of sight

noun

1. the straight line along which an observer looks or a beam of radiation travels

2. ophthalmol another term for line of vision

Word History and Origins

Origin of line of sight¹

First recorded in 1550–60