Scissors and shears use shear force as the blades press from either side, hence the name is justifiable.
Work Step by Step
Putting an object under shear stress means applying equal and opposite forces on each side of an imaginary plane that passes through the material. This is how scissors operate. One blade pushes down on the cardboard, and the other blade pushes up with an equally strong force nearby. The resulting shear stress acting on the cardboard between the blades causes it to fail. The name “shears” is justified.