The moth didn't coin 'bug'
Did you know Grace Hopper didn't coin the word 'bug'?
· 29-sec read
In September 1947, engineers on Harvard's Mark II found a moth stuck in a relay, taped it into the logbook and wrote "First actual case of bug being found." The joke only works because 'bug' already meant a fault: Thomas Edison was talking about bugs in his inventions in the 1870s. Grace Hopper was on the Mark II team and helped popularize the story, but the Smithsonian says the logbook was probably not hers.
Popular version vs. what really happened
Popular version
Popular version: Grace Hopper found a moth and coined 'bug'.
What really happened
Reality: the term is about 70 years older (Edison), the note is a joke on an existing word, and the entry is probably not in Hopper's handwriting.
Why it matters
The best postmortem stories get simplified as they're retold, so keep the original artifact (the log) as your source of truth.
Sources
High confidenceChecked October 20, 2026.