an item of incidental information.
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.
light coming from the side.
a window or other aperture for light in the side of a building, ship, etc.
a window at the side of a door or another window.

Origin of sidelight

First recorded in 1600–10; side1 + light1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sidelight

Contemporary Examples of sidelight

  • A callous and utterly botched effort, but even if just a sidelight to this execution, it fits the execution like a favorite glove.

    The Daily Beast logo
    India’s Twisted Conscience on Terrorism

    Dilip D’Souza

    February 16, 2013

  • As a(nother) sidelight, it's clear that Romney or whoever wrote this piece doesn't actually understand what culture even is.

    The Daily Beast logo
    Romney and Culture: Flip-Flop-Flip!

    Michael Tomasky

    August 1, 2012

Historical Examples of sidelight

British Dictionary definitions for sidelight



light coming from the side
a side window
either of the two navigational running lights used by vessels at night, a red light on the port and a green on the starboard
British 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
additional or incidental information
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for sidelight

also side-light, c.1600, "light coming from the side," from side (adj.) + light (n.). Figurative meaning "incidental information on a subject" is attested from 1862.

Online Etymology Dictionary, © 2010 Douglas Harper