Frame: The are three components to a frame: sill, header, and jamb. They hold the operating and/or stationary sash.

Sill: The frame member that runs horizontally across the bottom of the frame outside.

Header: The frame member that runs horizontally across the top of the frame.

Jamb: The part of the frame that runs vertically between the header and sill.

Sash: This is what you probably think of as the "window." It's the main section, whether operating (i.e., able to open) or stationary, that's installed into a frame. It's made of horizontal rails and vertical stiles.

Stop: The vertical piece that holds the lower sash in the frame on the inside.

Parting Bead: The thin vertial component that seperates the upper and loser sash.

Lite: A single area of glass or window pane.

Bar: The vertical or horizontal piece that divides the glass area into lites or panes.

Muntins: The bars that divide the glass area into lites or panes.

Hardware: The operating components of your window or door: locks, handles, hinges, etc.