Double-Hung Window, Muntins, Meeting Rail
1. Double hung window
A window hung with two sashes that are moveable up and down.
2. Meeting rail (red)
The part of a window where two sets of panes meet and overlap.
3. Muntins (yellow)
A muntin is a wooden frame, called a secondary framing member, to hold panes within a window.
Pictured is a 12 over 12 (the number of panes), double hung window like the ones found throughout Carpenters' Hall. Some windows in the Hall are 8 over 12; that is, they have 8 panes on top with a meeting rail separating it from the 12 panes on the bottom.
This window is also ornamented by a keystone at the top (Read more about keystones).