Y2k Frederick's of Hollywood Cobalt Blue Halter Slip Dress size Medium?

Sexy cobalt blue halter slip dress with an elastic waist and adjustable strap. Features lace triangular cup halter top with sheer mesh outside layer and an open upper back. Would be so cute styled as a going out top or worn as lingerie The size tag is missing, please see the photo of the approximate flat lay waist measurement. Based on information online, I suspect this is a medium