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

Example Sentences

Its site at the Arboretum is in line of sight of the Armed Forces Memorial and in an area where there are also other war memorials.

From BBC

Both helicopters maneuvered for better line of sight in the hopes of reestablishing communication with the group supervisor, according to the report.

From Los Angeles Times

In a semi-rural location, it has a good line of sight and as radio waves travel in a straight line , it is easy for a pilot to move things in.

From BBC

Some of the photographs are arranged freely, as if to follow the line of sight as it traces figures in a space — wind-scattered.

From Los Angeles Times

In a statement the CAA said it was working with companies to make drone operations beyond visual line of sight "a safe and every day reality".

From BBC