NWT VINTAGE Lilac Midi Dress Scarf Neckline 2X 40

Lovely vintage never-worn pinkish-lilac color dress. Features scarf neckline with 3-button opening at shoulder. Fabric, brand, and size tags are missing. Guessing a size 1X or 2X so please see measurements. Excellent condition. Still has price tag attached and on this tag is states the size is 40. Not sure what that translates to, 2X? Approximate Measurements: Armpit to armpit: 23" Length: 43" Sleeve Length: 18" Not sure of vintage age. Many vintage items listed.