Million Dollar Bug
Noun · Slang & Abbreviations
Definitions
A bug with very large financial consequences, either directly or through outages, fines, or damaged business. In engineering slang, the phrase is literal often enough that nobody laughs for very long.
In plain English: A bug that causes very large financial damage.
Example: "The decimal-rounding issue turned into a million dollar bug once billing corrections, support labor, and refund obligations were fully counted."