line of sight

American  

[lahyn uhv sahyt] / ˈlaɪn əv ˈsaɪt /

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.

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line of sight British  

noun

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

2. ophthalmol another term for line of vision

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Etymology

Origin of line of sight

First recorded in 1550–60

Example Sentences

Always in each other’s line of sight, always negotiating space that didn’t exist.

From Los Angeles Times • Apr. 3, 2026

Additionally, Arcuri said he doesn’t think Intel would’ve retaken ownership of the Ireland fab if it didn’t have “a good line of sight over potential foundry wins.”

From MarketWatch • Apr. 2, 2026

“With line of sight on the terminal level of Fed Funds this cycle and hopefully a stabilizing labor market, we believe the banks should continue their outperformance,” the firm wrote in a note last week.

From Barron's • Jan. 14, 2026

Companies may have a clearer path ahead after federal regulators in August proposed a rule paving the way for more drones to operate beyond so-called visual line of sight.

From The Wall Street Journal • Jan. 11, 2026

Instead, they would run back and forth at one end of the field, in her direct line of sight, so she could keep an eye on them.

From "Outcasts United: An American Town, a Refugee Team, and One Woman's Quest to Make a Difference" by Warren St. John