Just «like that», but also worn on top of a shirt, to wear them a bit less «dressed up». (redreidinghood.com)
A gown is basically worn above on top of a shirt or a blouse. (mayloz.com)
In an effort to wear layers and create a new outfit, I layered a sleeveless button down on top of my shirt dress which resulted in an outfit that Mademoiselle Chanel would approve of! (fauxionista.com)