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 band or ribbon worn about the waist as part of one's clothing or over the shoulder as a symbol of rank. transitive v. To put a band or ribbon about (the waist). n. A frame in which the panes of a window or door are set. transitive v. To furnish with a sash.