I came across the word "imprimatur," when reading about Iowa being a "...wonderfully Midwestern place to put their imprimatur on one, perhaps two..., of the Democratic contenders for the White House."

I hadn't heard it before. How is it used to describe an "official" approval?

Imprimatur is "new" Latin, and literally means "let it be printed". It comes from the Roman Catholic church, from the time when the episcopal authorities had control over what was printed, and exercised censorship. Without the Church's stamp of approval, publication was impossible.

It has since come to mean a mark of [official] approval.

Ohhh, that makes sense! Shu thought it had something to do with the Vatican, but I couldn't find that in the dictionaries.

Imprimatur has a sibling that you usually see hanging around: nihil obstat meaning "nothing stands in the way (of its printing)".

jheem gave a related term. Here's a compare-and-contrast, from the press:

Harvard chose this week to announce H Bomb, a student-run magazine that will feature erotic writing and nude photography. Apparently college students need to be reminded of sex, lest it slip their busy, knowledge-seeking minds.

H Bomb isn't some fly-by-night, off-campus venture, furtively circulated like a samizdat pamphlet. It's above-board, having received the imprimatur of Harvard's Committee on College Life.

[The] head of the Committee [said that] "while the committee was aware that the proposed content could be found offensive to some, it was equally aware that to deny recognition would deny free speech." Somehow I doubt that such a defense would carry much weight from a student accused of making an untoward sexual advance to a fellow undergraduate.

shufitz' samizdat reminds me of another bookish term: incunabula, from the Latin word for swaddling clothes or cradle, it means books printed before 1501. And from the printing industry, I've always been partial to quoin 'a wedge-shaped block used to lock type in a chase' (from A-H).

Incunabula also means the very earlier products of any art, not necessarily limited to book-printing.

In researching to confirm this, I found that this broader meaning seems to be the original meaning of the word. According to an old Britanica, the particularization to books "may have originated with the title of the first separately published list of 15th-century books, Cornelius a Beughems Incunabula typo graphiae (Amsterdam, 1688).

That source adds, "The word is generally recognized all over Europe and has produced vernacular forms such as the French incunables, German Inkunabein (Wiegendrucke), Italian incunaboli."