# millennium bug

> English word · Proper noun

## Definitions
1. A design flaw in computer systems that represented years as two digits (e.g. 84 for 1984), which could cause date calculations to fail if they involved years later than 1999.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/millennium-bug