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.
Lap and Sash: Combination of the two above (two separate belts). Mainly used in the 1960s and 1970s, usually in the rear. Three-point: three-point belts combine a sah and a lap belt in a single construction, securely anchored to strong points in the vehicle body. This helps spread out the energy of the moving body in a collision over the chest, pelvis, and shoulders.