A cummerbund is a broad waist sash, usually pleated, which is often worn with single-breasted dinner jackets (AmE:tuxedos) . The cummerbund was first adopted by British military officers in colonial India and later spread to civilian use. The modern day use of the cummerbund is as a component of semi-formal or black tie dress.
The name comes from the Urdu for waist restraint (kamar "waist" and band which means "to close") and was borrowed into English from the Urdu word meaning "loinband" in 1616. The word "cummerband" (see below), and less commonly the German spelling "kummerbund"(ribbon of sorrow), are often used synonymously with "cummerbund" in English. The word is also quite commonly misspelled and mispronounced as "cumberbun" or "cumberband".
Cummerbunds were traditionally worn with pleats facing up in order to hold ticket stubs and similar items. The contemporary use of the cummerbund is purely aesthetic. According to Alan Flusser (Dressing the Man, 2002, p. 246), it provides a transition between the shirt and the waistband.
While matching colourful ties and cummerbunds that are neither black satin or grosgrain are common, it is considered contrived by Flusser.
Additionally the cummerbund is commonly used to accommodate the expanding girth of gentlemen during a large meal.
This has gone out of fashion in the past few decades as the Colonies have moved away from their Imperial roots.
'The Cummerbund' is also a nonsense poem by Edward Lear, fully titled 'The Cummerbund, a poem from India', where it refers to the cummerbund as a ferocious woman-eating beast.