A little black number is a black dress or outfit, usually simple in cut but flattering, the kind of thing someone keeps in the wardrobe for an evening out or a smart event at short notice. The phrase is almost always approving, often said with a touch of admiration about how well it suits the wearer. “Number” here just stands in for “garment” or “outfit”, so the phrase can stretch to a suit, a top or any other black item, though it is most at home describing a dress. Unlike going fully black-on-black, where every piece of an outfit matches, a little black number is usually just the one garment doing the work.
What’s the origin of the phrase ‘little black number’?
The phrase draws on two older strands of usage that eventually met. The first is “number” itself as a word for a piece of clothing, a sense the Oxford English Dictionary traces back to the late 19th century. That generic clothing sense was already well established by 1935, when the Ladies’ Home Journal described a character as having “swathed herself in an afternoon number”, with no colour attached at all. The “little ___ number” pattern for a garment also turns up in Marguerite Steen’s 1953 novel Anna Fitzalan, which describes “an exquisite but throat-high ‘little number’ redeemed by lumps of jade”.
The second strand is the little black dress as a fashion idea, which is firmly tied to Vogue’s 1926 feature on a plain Chanel design. The magazine did not call it a “little black number” but nicknamed it “Chanel’s Ford”, comparing its mass appeal to the Model T car, according to Amy Holman Edelman’s 1998 book The Little Black Dress.
These threads of plain black dressing and “number” as slang for an item of clothing ran alongside each other for decades before converging into the specific colour-plus-number phrasing familiar today. Green’s Dictionary of Slang records a British example from 1986 that shows the pairing directly: “Vicki came in, clad elegantly in a flimsy black number.” Interestingly, “number” applied to a woman rather than her clothes had earlier form too: “hot number” is recorded from 1919 as a term of disgust rather than admiration, a reminder that the word has shifted in tone over time. No source pins down a first appearance of the exact compound “little black number”, so it looks less like a single coinage than the natural meeting point of these older habits of speech.