n.1. a. An open framework made of strips of metal, wood, or similar material overlapped or overlaid in a regular, usually crisscross pattern.
b. A structure, such as a window, screen, or trellis, made of or containing such a framework.
2. Something, such as a decorative motif or heraldic bearing, that resembles an open, patterned framework.
3. Physics a. A regular, periodic configuration of points, particles, or objects throughout an area or a space, especially the arrangement of ions or molecules in a crystalline solid.
b. The spatial arrangement of fissionable and nonfissionable materials in a nuclear reactor.