The best I can describe it is as an apron. It still has pleating at the waistline (held in place by seam binding); each side is folded back with evidence of where it was attached to another piece of material; there is seam binding at the bottom; and it is backed with an open-weave lining that probably also adds some stiffening to it.
The material is in excellent condition with a gorgeous print.
Hope you can use it in another project, or finish it off as is.
Across at waist (includes the fold-back of about an inch on each side)--12-5/8"
Length down the sides--29-1/2"
Across at the bottom--35"