Pent Up.

Stand back.

Dear Word Detective: I’ve written a play that takes place in 1880, and the linguists in my life insist that the phrase “pent up” is a twentieth century phrase. I cannot imagine an audience member throwing his hands up in disgust and storming out of the theater the instant he heard the Victorian-garbed actor utter the phrase “pent up,” but for the sake of accuracy, does that phrase belong in my 1880 play? — Daniel Tobias.

Oh goody, another theatrical anachronism question. I actually get quite a few of these from playwrights and screenwriters striving to avoid those “Julius Caesar glanced impatiently at his wristwatch” moments that reviewers love to mock. In fact, I usually answer such questions by email even when I don’t use them in a column, and I like to think I’m single-handedly keeping both Hollywood and the American theater world on an even keel, historical-accuracy-wise. Yes, I like to think that, despite voluminous evidence to the contrary. The least they could do is pay attention to my warnings about Ralph Fiennes. I still can’t believe I sat through The English Patient.

Not to devalue my own role in your play, but I too tend to doubt that today’s theatergoers are likely to freak out and start throwing rotten vegetables upon encountering one little anachronism. But one never knows when the audience may contain a disgruntled etymologist with a short fuse (don’t laugh, I know a few), so here goes.

The good news is that your linguist friends are wrong, and apparently lazy to boot, because even a cursory glance at the Oxford English Dictionary (OED) acquits “pent up” of being absent for the 19th century. As a matter of fact, the first printed appearance of “pent up” in the modern figurative sense of “held in or back under pressure” (OED) found so far dates back to the 17th century (“Whil’st boyling rage (pent up) last high did swell,” William Alexander, 1637). That’s a pretty good cushion against a charge of anachronism.

The literal sense of “pent up” when it appeared earlier, in the 16th century, was “confining,” as in a small room. Interestingly, “pent up” apparently arose as an emphatic form of the adjective “pent,” meaning “closely confined” or “held back under pressure.” This “pent” was actually the past participle of the verb “to pend,” which itself was a form of “to pen,” which meant to confine something or someone in an actual pen or cage.