What do you call the hard part between the different panes of glass in a window?
You see the white horizontal and vertical bars between the panes of glass in the windows? What do you call them? Is there a name for them?
In the UK they are muntins, or glazing bars.
In the double-glazed replacement window market they are often called Georgian bar.
It’s called a grille - see https://www.thefreedictionary.com/grille
A grating of metal, wood, or another material used as a screen, divider, barrier, or decorative element, as in a window or on the front end of an automobile.
EDIT: the word muntin (I just learned) actually seems more specific to separating panes of glass in windows: https://en.m.wikipedia.org/wiki/Muntin
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".
This Wikipedia article also notes the following about using the word grille:
Many companies use the term "grille" when referring to a decorative structure of wood or other material that is put over a single pane of glass to make it look as if there were muntins separating multiple panes of glass. In the UK, the term "grille" tends to be used only when there are bars sandwiched within the insulated glass glazing unit, and not stuck to the outsides of it.