The internal force acting over a cross-sectional area within the material is termed stress, whereas the force applied per unit area typically used inside a fluid is termed pressure.
Difference between stress and pressure
|Stress can be defined as the internal resistive force to the deformation per unit area.||Pressure can be defined as the amount of force applied per unit area.|
|Due to stress, the pressure will not be developed.||Due to pressure, stress will be developed.|
|Stress can be either a positive or a negative force||The pressure is always a positive force|
|Pressure is exerted externally||Stress is developed internally|
|Stress may be tensile, compressive and shear||The pressure is always compressive|
|The magnitude of stress at a point in a different direction is different.||The magnitude of the pressure at a point in all the directions remains the same.|