Blouse wiki:
ouse most commonly refers to a woman's shirt, although the term is also used for some men's military uniform shirts.Blouses are often made of cotton or silk cloth and may or may not include a collar and sleeves. They are generally more tailored than simple knit tops, and may contain "feminine" details such as ruffles or embroidered decorations.Blouses have buttons reversed from that of a men's shirts. That is, the buttons are normally on the wearer's left-hand and the buttonholes are on the right. The reasons for this are unclear, however. Some suggest this custom was introduced by launderers so they could distinguish between women's and men's shirts. Another theory purports that the tradition arose in the middle ages when one manner of manifesting wealth was by the number of buttons one wore. Female servants were in charge of buttonning their mistresse's gowns (since the buttons were usually in the back). Tiring of attempting to button the buttons backwards, they started reversing the direction of the buttons.
See more at Wikipedia.org...