sidelight

American  

[sahyd-lahyt] / ˈsaɪdˌlaɪt /

noun

1. an item of incidental information.

2. either of two lights carried by a vessel under way at night, a red one on the port side and a green on the starboard.

3. light coming from the side.

4. a window or other aperture for light in the side of a building, ship, etc.

5. a window at the side of a door or another window.

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sidelight British  

/ ˈsaɪdˌlaɪt /

noun

1. light coming from the side

2. a side window

3. either of the two navigational running lights used by vessels at night, a red light on the port and a green on the starboard

4. either of two small lights on the front of a motor vehicle, used to indicate the presence of the vehicle at night rather than to assist the driver

5. additional or incidental information

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Etymology

Origin of sidelight

First recorded in 1600–10; side ¹ + light ¹

Example Sentences

Matthiessen considered his nonfiction career a sidelight to his real literary endeavors.

From The Wall Street Journal • Nov. 21, 2025

“It’s not all one guy outside the screen door with sidelight on him.”

From Los Angeles Times • Oct. 1, 2024

After four decades, Chapman's "sidelight" has become an American nightmare.

From Salon • Dec. 15, 2022

One intriguing sidelight to this game was the battle of premier Pac-12 running backs.

From Seattle Times • Nov. 11, 2017

I make it to the door first and peer out the glass sidelight.

From "Will Grayson, Will Grayson" by John Green and David Levithan