Glitch is from the German glitschen, via the Yiddish gletshn, meaning to slip. The term is technical jargon in the electronics world to describe what happens when the inputs of a circuit change. When this occurs, the outputs briefly spike to some random value before settling to the correct value. If the circuit is queried during a glitch, a wildly inaccurate response may result. From this it acquired a more general sense meaning any malfunction.1
The term gained popular currency through the U.S. space program. From John Glenn’s 1962 Into Orbit:
Another term we adopted to describe some of our problems was “glitch.” Literally, a glitch is a spike or change in voltage in an electrical circuit which takes place when the circuit suddenly has a new load put on it...A glitch...is such a minute change in voltage that no fuse could protect against it.2
1Historical Dictionary of American Slang, v. 1, A-G, edited by Jonathan Lighter (New York: Random House, 1994), 903.
Copyright 1997-2013, by David Wilton