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 sash for a modern window might include as many components as these: 1  Glass: Two sheets of glass for a double-paned window, one sheet for single panes. 2  Frame: Frame is a convenient term for the wood, fiberglass, vinyl, or metal parts that hold the glass together.