Window Treatment:   To “dress” or “cover” a window opening.  It is interchangeable with the term “Window Coverings”  (only difference is that it sounds posh and professional). Window coverings can be custom designed to specific measurements and styles.  It can be either functional or decorative, or both. Window coverings / treatments includes blinds, curtains, shutters, drapes, fabrics, hardware and tiebacks applied to the window opening and adjoining wall space.

Image via Anthropologie