Midriff refers to the area around a person’s middle, that is, the front of their body between the chest and the waist.

// Even the store’s winter line of clothing includes a number of midriff-baring tops, albeit paired with oversized cardigans or flannel shirts.

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“‘I can be terribly self-involved,’ he says, though you can’t be sure whether he’s warning her or bragging. She introduces him to her parents—an all but unwatchable clash of opposites, with Tomas rolling up late in a sheer black crop top, covered in dragons, that leaves his midriff bare.” — Anthony Lane, The New Yorker, 4 Aug. 2023

Today, the word midriff is likely to evoke a plummy tummy or some fab abs, but the “mid-torso” sense of midriff is relatively young, having bellied up to the bar of English usage only in the early 19th century. For most of its history, midriff has been used to refer to the diaphragm, the large flat muscle that separates the lungs from the stomach area (and contracts spasmodically when we hiccup). This diaphragm sense has been around for at least 1,000 years, with the earliest known uses of midriff—which comes from the Old English word hrif, meaning “womb” or “belly”—being found in manuscripts such as Bald’s Leechbook, a medical text that is believed to date back to the mid 10th century. To riff on the vernacular of the 21st century, that kind of lexical staying power is far from mid.