Bug

In computing, a bug is an error, flaw, or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. Bugs can range from minor glitches that cause aesthetic issues to critical defects that lead to system crashes, data corruption, or significant security vulnerabilities. The term "bug" is said to have originated from a moth found inside an early relay computer by computer pioneer Grace Hopper, though its use in engineering predates this incident.