Scram is an American slang verb meaning to depart, to get out. It probably is a clipping of scramble, but there is also the German verb schrammen, meaning to depart or run away. The German verb may have influenced or even been the root of the English slang term.
Scram makes its appearance in the late 1920s. From Walter Winchell’s column in the New York Evening Graphic of 4 October 1928:
His popular slang creations include..."scram," meaning “git out!”
The word is also a jargon term in the nuclear industry meaning to shutdown a nuclear reactor immediately or the emergency shutdown of a reactor. This use first appears in print in American Speech in 1950:
The point of neutron intensity at which the reactor is “scrammed"—shut down, automatically or otherwise.
But spoken use of the term almost certainly dates back to the first nuclear reactor at the University of Chicago in 1942. From Francois Kertesz’s 1968 The Language of Nuclear Science:
During the experiment that culminated on December 2, 1942 in the accomplishment of the first controlled nuclear chain reaction, a safety rod was held by a rope running through the pile and weighted on the opposite end. The young physicist in charge was told to watch the indicator; if it exceeded a certain value he was to cut the rope and scram. Since then the term scram is used to designate the emergency shutdown of a reactor. Today the urgency is lost and the word scram indicates simply a fast-shutdown operation.
Some claim that the specific nuclear use of the word was coined by Enrico Fermi himself, although it seems unlikely, but not entirely implausible, that a recent immigrant such as Fermi would have such a command of colloquial American English.
It’s also often claimed that scram is an acronym for safety control rod ax man, a reference to the 1942 procedure. This rather tortured acronym did not appear until much later and is in no way the origin of the nuclear term.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2015, by David Wilton