A-line dress

dress that is narrow at the top and flares out at the bottom

The fashion term A-Line was introduced by the French couture designer Christian Dior for his Spring-Summer 1955 Collection. It followed the "H" line of the previous Fall-Winter season, and describes the new silhouette of that collection. The "A-Line" silhouette replicated the letter "A" by flaring out from the top, like a funnel, narrow and fitted at the neck and shoulders, skimming the hips and widening toward the bottom, with little or no shaping or seaming at the waist. Any dress, coat or skirt that has a slender, funnel shape.
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