A term which refers to windows in which multiple individual panes of glass or lights are assembled in the sash using muntins. A window or door unit that opens or operates. Vinyl A plastic material used by some window manufacturers. Weatherstripping A material or device used to seal the openings, gaps or cracks of venting window and door units to prevent water and air infiltration. Windload Force exerted on a surface by moving air.
Windowpane divider See muntin.