Shear force refers to the force that acts parallel to the cross-section of a structural element, while bending moment is the moment that occurs when an external force is applied to the element causing it to bend.
Shear force and bending moment are one of the most important concepts in civil engineering under structural engineering.
Shear Force and Bending Moment Diagrams are powerful graphical methods that every Mechanical and Civil Engineer should know to analyze a beam under loading.