Lingerie is a term for fashionable and notionally alluring undergarments. It derives from the French word linge, "washables" — as in faire le linge, "do the laundry" — and ultimately from lin for washable linen, the fabric from which European undergarments were made before the general introduction of cotton from Egypt and then from India.

The term in the French language applies to all undergarments for either gender. In English it is applied specifically to those undergarments designed to be visually appealing or erotic, typically incorporating materials such as Lycra, nylon (nylon tricot), polyester, satin, lace, sheer and/or silk and not applied to functional cotton undergarments. It is commonly pronounced in English with a faux French pronunciation (such as LONJ-er-ee in British pronunciation or lonj-er-AY in American pronunciation). True French pronunciation is lan-ZHREE ((/læⁿˈʒri/).

The concept of lingerie being visually appealing was a development of the later nineteenth century. Lady Duff Gordon of Lucile, was one of the first pioneers on lingerie freeing women from restrictive corsets. Up through the first half of the 20th century women selected underwear for three major purposes: to alter their shape (first with corsets and later with girdles or bras), for reasons of hygiene, or for modesty. Women's underwear before the invention of the crinoline was often very large and bulky. As the 20th century progressed underwear became smaller and more form fitting. In the 1960s 'controversial' lingerie manufacturers such as Frederick's of Hollywood begin to glamorize lingerie and the idea of lingerie having a sexual appeal slowly developed.

The lingerie industry has expanded in the 21st century with designs that double as outerwear. The French refer to this as 'dessous-dessus' which basically means innerwear as outerwear. The boutique Faire Frou Frou, which is an antiquated phrase meaning "show it off", heralds this philosophy by categorizing lingerie as an accessory with details such as straps and lace trim that should be layered and shown as part of one's outerwear.