Arch

1. A structure, such as a freestanding monument, shaped like an inverted U.
2. A structure, especially one of masonry, forming the curved, pointed, or flat upper edge of an open space and supporting the weight above it, as in a bridge or doorway. Many bridges have beautiful graceful arches.
3. Anatomy. An organ or structure a curved or bowlike appearance, especially either of two arched sections of the bony structure of the foot. The army will reject men with feet having fallen arches.