A defect in code or machine, named after an insect that was taped into a logbook in 1947 and was not the first.
Documented
Edison had bugs before computers
Thomas Edison wrote in 1878 of bugs in his inventions, meaning faults. The word predates electronic computing by generations, a piece of engineering slang for the small things that break big things.
Assessment: Documented in Edison's correspondence. The metaphor was antique when the moth arrived.
Stories
The moth that founded an industry
The beloved story: Grace Hopper's team found a moth in the Harvard Mark II in 1947, taped it into the logbook, and the term was born. Museums display the page. The insect is authentic.
Assessment: The moth is real, the tape is real, the page survives. Only the word's birth certificate is forged.
Interesting claims
Read the fine print in the logbook
The entry itself reads: first actual case of bug being found. The joke only works if bug already means defect. The engineers were punning, not christening.
Assessment: Documented in the artifact's own handwriting. The most famous origin story in computing debunks itself.
Sources and further reading
Edison's 1878 letter on bugs in invention
1947 Harvard Mark II logbook, Smithsonian, with the taped moth
Peggy Kidwell, Stalking the Elusive Computer Bug (1998)
Oxford English Dictionary, bug, engineering sense
Worth asking
The museum label says one thing and the artifact says another. Which do visitors photograph?