millennium bug

American

noun

Informal.

a bug that could cause computers or software to misinterpret a year after 1999 as having the first two digits 19 instead of 20, due to the coding of dates using only the last two digits of the four-digit year.

millennium bug British

noun

computing any software problem arising from the change in date at the start of the 21st century

"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

Etymology

Origin of millennium bug

First recorded in 1990–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

To them, as they navigate world-threatening issues such as climate change and the coronavirus, the idea of the millennium bug seems quaint.

From New York Times • Feb. 14, 2022

Buzzfeed also reports that Mr Johnson called fears over the future of the Irish border "pure millennium bug stuff".

From BBC • Jun. 8, 2018

Throw in the kingdom-wide risk of plague – a different sort of millennium bug – and this could be a particularly pungent prequel.

From The Guardian • Aug. 24, 2015

In the popular memory, the millennium bug was something that failed to come to pass.

From BBC • Dec. 30, 2014

A large part of the misunderstanding stems from Dionysius Exiguus--Latin for "Dennis the Short"--a 6th century monk who should be thought of as the original millennium bug.

From Time Magazine Archive

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023