Slotted angle (also sometimes referred to as slotted angle iron) is a system of reusable metal strips used to construct shelving, frames, work benches, equipment stands and other structures. The name derives, first, from the use of elongated slots punched into the metal at uniform intervals to enable assembly of structures fixed with nuts and bolts, and second, from the longitudinal folding of the metal strips to form a right angle. 

Slotted angle is a system of reusable metal strips used to build shelving, frames, work benches, equipment stands, and other constructions. Slotted angle is also frequently referred to as slotted angle iron. The term comes from two things: first, the usage of extended slots that are punched into metal at regular intervals to permit the assembly of structures fastened with nuts and bolts, and second, the longitudinal folding of the metal strips to form a right angle.