This is a vintage petite women's purple and blue fit and flare dress from Petites By Willi in size 6.
It measures about 17" underarm to underarm, 12" across the waist, 43.5" from the back of the neck to the bottom hem, 21.5" shoulder to sleeve, 14" shoulder to shoulder, 14" hip to hip, 27" waist to bottom hem, and 40" shoulder to hem when laid flat.
The dress is in good pre-owned condition.