This is an architectural term found only in Ezek. 40:16, 21-22, 26, 29.
There is no absolute proof that the early Israelites used arches in their buildings. The arch was used in building the pyramids of Egypt. The oldest existing arch is at Thebes, and bears the date B.C. 1350. There are also still found the remains of an arch, known as Robinson’s Arch, of the bridge connecting Zion and Moriah.