Sorry, no definitions found.
Sorry, no etymologies found.
Proof comes from the term bulshytt, which appears early on and seems to have a clear predecessor in our own language.
My favorite Stephensonism here is "bulshytt," which doesn't mean exactly what you think it might.
But don't let this seeming coincidence fool you: bulshytt is a very specific term with its own etymology - although its usage does seem to match a well-known English term.