a jack consisting of the union of a national flag or ensign, as the U.S. jack, which has the white stars and blue field of the union of the U.S. national flag.
(often initial capital letter) the British national flag.
any flag the overall design of which is a union.
a common name for Union flag
(often not capitals) a national flag flown at the jackstaff of a vessel
First recorded in 1665–75
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Currently the Senedd flies two Welsh flags and one Union flag - commonly known as the union jack - at the front of the building, alongside the flag of Ukraine.
From BBC • May 22, 2026
Geri Halliwell's union jack flag platform boots are also among items featuring in the free exhibition at the Barbican Music Library, along with Liam Gallagher's tambourine and a Brit Award.
From BBC • Apr. 16, 2026
And yet, in a parallel world, it could have been the red, white and blue of the union jack flying in her honour, and not that of the French flag.
From BBC • Feb. 18, 2026
Nottinghamshire County Council has said it is "extremely disappointed" after one of its union jack flag banners was vandalised in Newark.
From BBC • Jan. 7, 2026
On one side was represented an engagement in which the American soldiers, led by Washington, were fighting under the old flag—thirteen stripes and the union jack.
From Three Years in the Sixth Corps A Concise Narrative of Events in the Army of the Potomac, from 1861 to the Close of the Rebellion, April, 1865 by Stevens, George T.
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
