1. 1. A framed section of a window or door that is usually filled with a sheet of glass or other transparent material.
   2. The transparent material used to fill such a section.
2. A panel, as of a door or wall.
3. One of the flat surfaces or facets of an object, such as a bolt, having many sides.

[Middle English, section, pane of glass, from Old French pan, piece of cloth, panel, from Latin pannus, cloth.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.