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.
Determine the length of your sash belt. Measure your waist and add at least 12 inches to the measurement for use with a belt buckle, and 24 inches if you plan to tie your sash. Decide how wide you want your sash belt to be. Double the width of sash and add 1 inch for seams. For example, if your waist is 30 inches and you want to tie your sash, you will need at least 54 inches of fabric for the length. If your sash will be three inches wide, cut the strip of fabric 7 inches wide.