This is such a classic "power suit" style dress from the 80s.  A respectable espresso brown 100% cotton dress has absolutely massive shoulder pads, and a sexy pencil style skirt.  There are two pockets at the front, and this buttons all the way down.  The neckline is a V, bordered by large lapels that are secured by buttons, and then a smaller collar that hugs the neck. 

There was likely a belt to go with this at some point, but it is no longer with the dress. 

This is marked size 7/8 . Based on measurements, this fits like a modern size 2-4.  For best fit, please compare the measurements below to your own, or to the size chart of a brand that fits you well. 

Chest: 36"
Waist: 28"
Hips: 36"
Shoulder to hem: 41"