Truss
Truss is a frame made of triangles that holds up bridges and roofs.
Think of it this way
A wooden dish rack holds wet dishes upright using a grid of angled wooden rods. Each rod leans into the next, forming small triangles across the rack. No single rod carries all the weight — the triangles spread the load to every part of the frame. A truss works the same way: triangles lock together so no single beam bends or breaks.
Explaining truss by grade level
A truss uses triangles to hold things up. Triangles are strong shapes that do not bend. When you build a bridge with triangles, it can hold a lot of weight. Squares can fold flat, but triangles stay firm.