(σ) experienced within a solid is the magnitude of the force acting F, divided by the area A over which it acts:

stress = force / area of surface on which force acts

σ = F / A

Its SI unit is the pascal (Pa), where 1 Pa = 1 N / m2. Thus, if a cane supports a load of stress at any point within the cane is the load divided by the cross-sectional area at that point; the narrowest regions experience the greatest stress.