1) Dress 2) Frock 
A coatdress or coat dress is a woman`s dress that resembles an overcoat, usually with collar, lapels and front fastenings similar to a coat, and made in spring- or autumn-weight fabrics. The modern coatdress first emerged in the 1910s, with a 1915 article in Vogue assuring readers that the new garment could be worn over waistcoats or underdresses....
[n] - a dress that is tailored like a coat and buttons up the front
noun a dress that is tailored like a coat and buttons up the front
a tailored dress of medium or heavy fabric, styled like a coat and worn in place of a suit or similar outfit.