Fits close through the bodice, then flares gently from the waist to trace the letter A.
Also called: a line, princess seam
The basics
What to know about a-line
An A-line holds the bodice, the fitted upper section of the dress, close to the body. From the natural waist it widens steadily to the hem, so the outline traces a capital A. The flare comes from the pattern, not from gathering. Panels are cut wider at the bottom than the top, often joined by princess seams. Those are the vertical seams running from shoulder or armhole down over the bust, and they shape the fit without darts.
That geometry is why the shape works so broadly. The waist is defined, because the flare starts exactly there. But the hip and thigh are never measured by the dress; the fabric passes them at a distance. Skimming rather than gripping means an A-line tolerates a size of fluctuation that would defeat a sheath. It keeps its line whether you sit, walk or climb stairs.
The cut carries every length and almost every register: a mini A-line in cotton reads casual. Meanwhile, the same lines at midi in crepe read ceremonial. Drama is the trade-off. An A-line flatters quietly and never makes the waist the event the way a fit and flare does. In stiff fabric the flare can read boxy from the front. Hold the skirt out, let it drop, and watch how it falls.
In photos
A-Line on real products
See this option on different products. Open a photo for a larger view, or select the name to read its guide.