panes

1. An individual sheet of glass in a window, door, etc.
2. A layer in the build-up of a GUI.
3. A division; a distinct piece or compartment of any surface.
4. A square of a checkered or plaid pattern.
5. One of the openings in a slashed garment, showing the bright colored silk, or the like, within; hence, the piece of colored or other stuff so shown.
6. A compartment of a surface, or a flat space; hence, one side or face of a building.

   An octagonal tower is said to have eight panes.

7. A subdivision of an irrigated surface between a feeder and an outlet drain.
8. One of the flat surfaces, or facets, of any object having several sides.
9. One of the eight facets surrounding the table of a brilliant-cut diamond.

noun

The (often spherical) end of the head of a hammer opposite the main hammering end.