Rebar, short for reinforcing bar, is a common steel bar or mesh of steel wires used as a tensioning device in reinforced concrete and reinforced masonry structures to strengthen and hold the concrete in tension. It ensures that a structure can withstand the stresses and pressures exerted upon it, preventing the concrete from cracking or collapsing under strain. Made primarily of carbon steel and fabricated in a variety of grades, sizes, and strengths to cater to different structural requirements, rebar significantly improves the durability and longevity of structures. Its surface is often ribbed to enhance the binding with concrete.