Edison Movie reference 1940 I just heard a bug reference in the movie Edison The Man 1940 towards the end of the movie when Edison determines that his two dynamos have a problem because the speed governors were not synced until he mechanically linked them His first erroneous attempt caused the dynamos to act as a motor generator combo until the governors were mechanically linked He wanted the dynamos to work as parallel generators In the movie Spencer Tracy distinctly used the term bugs for this problem when he first attempted to light up New York City Granted this is a movie But the term bug was obviously used during Edison s invention period for mechanical design issues that needed to be resolved and thus included in the movie Re quoting the previous Edison quote Bugs as such little faults and difficulties are called And the movie itself is from 1940 which is earlier than when it was first used for software It seems likely that bugs was an engineering term before it made it into software