Then you probably haven't been around physicists, or read enough physics-related material. A non-scholarly reference which can't be easily checked online is George Dyson's "Project Orion," where Freeman Dyson (author's father) is quoted as mentioning this or that "code" as significant for the design of various Orion parts. (That should be a native enough English speaker.) The time-frame is late 1950s to early 1960s.