Properly only an opening in a house for the admission of light and air, covered with lattice-work, which might be opened or closed (2 Kings 1:2; Acts 20:9). The spies in Jericho and Paul at Damascus were let down from the windows of houses abutting on the town wall (Joshua 2:15; 2 Corinthians 11:33). The clouds are metaphorically called the "windows of heaven" (Genesis 7:11; Malachi 3:10). The word thus rendered in Isaiah 54:12 ought rather to be rendered "battlements" (LXX., "bulwarks;" R.V., "pinnacles"), or as Gesenius renders it, "notched battlements, i.e., suns or rays of the sun"= having a radiated appearance like the sun.

Noah Webster's New International Dictionary of the English Language

1. (n.) An opening in the wall of a building for the admission of light and air, usually closed by casements or sashes containing some transparent material, as glass, and capable of being opened and shut at pleasure.

2. (n.) The shutter, casement, sash with its fittings, or other framework, which closes a window opening.

3. (n.) A figure formed of lines crossing each other.

4. (v. t.) To furnish with windows.

5. (v. t.) To place at or in a window.