Not too happy with you using autism to call someone dumb, but I'll leave this up assuming it was just a one-off.
Definition of sash for Students. 1  1 : a frame for a pane of glass in a door or window. 2  2 : the movable part of a window.
A piece of glass surrounded by wood, a pane. Often used when referring to multiple panes (a window, a pane of glass within a window). Lower Sash. The bottom portion of the window comprised of a pane of glass set inside a frame. Is fixed on a single hung window and slides up and down in a double hung window. Molding