Computer Bug Found
on 9 September 1947,
US Navy technician fixed a fault in a Harvard Mark II computer by removing a moth that was caught between the contacts of a relay in the system.
This event is often thought to be the origin of the terms, “bug” and “debug“, in reference to computer problems.
Even though use of word “bug” in other device is actually in Pall Mall Gazette from 1889
sources: various sources