print standard
A print standard is the published rule a file has to satisfy for a printing works to run it exactly as it arrives.
In more detail
Before a press starts, somebody has to know four things: which press the colours were mixed for, what the job is called, whether the touching colours have already been made to overlap so that no white line opens along the join, and where the blade goes on every page. A file that carries none of them costs a morning of telephone calls; a file that carries all four is opened and run.
A print standard is that list, written down once by the trade and published, so that a printing works can name what it wants in two words and a program can be held to it. For PDF documents the one everybody names is PDF/X.
What it does on a real document
The engine checks the four before it writes a single byte, and refuses the document naming the first one missing. A refusal on your own machine costs a minute; the same fault found at the printing works costs a print run.
Ask your printing works which one they want, in those words, and the answer comes back in two: they name it every day.
Where it comes from, and why
The rules came from the printing trade rather than from the makers of the software. Firms exchanging jobs wanted one list they could all point at instead of a house style each, and the committee that wrote it was made of printers and publishers.
See it on a finished document
A sheet prepared for the printing works A sheet as it goes to the press The page that goes further on this word