A little black dress is an evening or cocktail dress, cut simply and often with a short skirt. Fashion historians ascribe the origins of the little black dress to the 1920s designs of Coco Chanel, intended to be long-lasting, versatile, affordable, accessible to the widest market possible and in a neutral color. Its continued ubiquity is such that many refer to it by the abbreviation LBD.

The "little black dress" is considered essential to a complete wardrobe by many women and fashion observers, who believe it a "rule of fashion" that every woman should own a simple, elegant black dress that can be dressed up or down depending on the occasion: for example, worn with a jacket and pumps for daytime business wear or with more ornate jewelry and accessories for evening. Because it is meant to be a staple of the wardrobe for a number of years, the style of the little black dress ideally should be as simple as possible: a short black dress that is too clearly part of a trend would not qualify because it would soon appear dated.

(Source: wikipedia.org)