English

Noun

Union Jack ‎(uncountable)

The Union jack of the United Kingdom. Flag Ratio: 1:2

1. The flag of the United Kingdom, consisting of the flags of England (St. George's Cross), Scotland (St. Andrew's Cross), and Ireland (St. Patrick's Cross) now only used in Northern Ireland combined.
2. (nautical, Britain) The flag, consisting of the flags of England, Scotland, and Northern Ireland combined, flown on ships of the government of the United Kingdom

US Union Jack

1. (nautical, US) The flag, consisting of the blue star-studded field in the corner of the national ensign, flown at the jack staff by ships at anchor^[1].

Translations

Usage notes

The Union Jack (also Union flag, union jack) is regarded as the official flag of the United Kingdom, although technically no law to that effect has ever been passed.

References

1. ↑ US FM 55-501 MARINE CREWMAN’S HANDBOOK; 1 December 1999