What is the difference between a column, a beam and a brace in steel structures?

Columns are vertical members that primarily carry axial compression from above (dead load, live load, roof load) down to foundations. They are checked for compression, buckling, and combined compression + bending. Typical profiles: HEB, W-shapes, SHS (square hollow sections). Beams are horizontal members that carry loads perpendicular to their axis — transverse loads cause bending moment and shear. They are checked for flexure, shear, lateral-torsional buckling and deflection. Typical profiles: IPE, W-shapes, ISMB. Braces are diagonal members that carry axial forces only (tension or compression) to provide lateral stability to a frame. They are checked for pure axial capacity. Typical profiles: L-angles, hollow sections, rods. A single structural member can act as more than one depending on loading (a beam-column carries both axial force and bending).