The term 'debugging' was popularized after engineers found a literal moth stuck in a computer relay in 1947 — and taped it into the logbook.

The team working on the Harvard Mark II, including computing pioneer Grace Hopper, removed the moth and noted it as the 'first actual case of bug being found.' The insect itself, still taped to the page, survives in a museum. People had used 'bug' for technical faults before, but the moth cemented the word in computing lore.