The answer to the crossword question “Part of a window” is SASH. A window sash is a frame that holds the glass panes of a window. It can be opened for ventilation or closed to keep the elements out. A sash is typically made of wood, vinyl, or metal and can slide up and down or tilt in for easy cleaning. Window sashes are an important component of a window and play an important role in the overall functionality and aesthetics of a building.