muntin

thumb|Diagonal muntins separating diamond-shaped panes of glass in a casement window. thumb|Muntins divide each window into six panes of glass. Rounded mullions separate the three casement windows. [[Nový Bor, the Czech Republic.]]

A muntin (US), muntin bar, glazing bar (UK), or sash bar is a strip of wood or metal separating and holding panes of glass in a window. Muntins can be found in doors, windows, and furniture, typically in Western styles of architecture. Muntins divide a single window sash or casement into a grid system of small panes of glass, called "lights" or "lites".