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Parts of a Window and Window Frame (Diagrams)

Photo collage of different types of window frame.

When you’re replacing windows, it’s nice to know all the different parts of the window and window frame. That’s here these 2 diagrams come into play. The first illustrates the anatomy of a window and frame.

The second showcases the anatomy of a cross-section of a three-pane window.

Diagram: Parts of a Window

Parts of a window and window frame diagram

  • Interior Casing: The finished trim or holdings around the window frames. They help prevent cold air from entering as well as add a finishing touch and enhance the overall look of the window.
  • Head: The horizontal part of the window frame.
  • Muntin: A bar or strip of wood or metal between adjacent panes of glass that create a grid or latticework appearance.
  • Sash Lock: The locking mechanism attached to a single-hung or double-hung window.
  • Upper Sash (Upper Panel): The upper part of the fixed or movable framework holding the pane of a window.
  • Side Jamb: The vertical parts that form the sides of a window frame.
  • Stile: Vertical members of the window frame.
  • Window Pane: A plate of glass within a window frame.
  • Lower Sash (Lower Panel): The lower part of the fixed or movable framework holding the pane of a window.
  • Channel: A groove around windows.
  • Exterior Sill: The external horizontal bottom part of the frame that protects from water intrusion and can be used as a decorative element.
  • Apron: The decorative raised section below the window sill.
  • Stool: The bottom horizontal shelf of the window attached to the window sill where the sash descends and where plants may be placed.
  • Bottom Rail: The lowest horizontal part of the window frame that connects its vertical parts.
  • Top Rail: The top horizontal part of the window frame.
  • Head Jamb: The vertical side on the the very top of a window frame where the window sash sits on.

Cross-Section Illustration of a Window

Cross section diagram of a window and window frame

  • Air Latch: Makes it possible to keep the window open regardless of the position you set it.
  • Aluminum Bracket: Brackets made of aluminium and part of a window bracket system that offsets the window from the wall by a few inches.
  • Glass Sealant: A silicone-based product that can take on the form of a liquid, gel or foam and applied to glass surfaces as a protective coating and to preserve its clean and dry exterior.
  • Hollow Glass: Window panes made of hollow glass.
  • Pane: A sheet of glass in a window.
  • Spacer: An insulating glass unit typically made of aluminium that’s sealed between two glass layers and keep glass panes apart.
  • Meeting Rail: The horizontal rail of a sash that meets the rail of the other sash when the window is closed.
  • Pulley: A simple machine with a wheel and a rope or chain used to lift heavy objects.
  • Sloped Sill: The exterior part of the window sill that is designed to be sloped downward to enable water to run off.
  • Drain Hole: A short channel where fluids can flow.
  • Lift Rail: A handle used to open and close a window that goes all the way across the sash.
  • Lower Sash: The lower part of the fixed or movable framework holding the pane of a window.
  • Glass Sealant: A silicone-based product that can take on the form of a liquid, gel or foam and applied to glass surfaces as a protective coating and to preserve its clean and dry exterior.
  • Bottom Rail: The lowest horizontal part of the window frame that connects its vertical parts.
  • Frame: The framework that makes up the window’s perimeter and supports the entire window system.