The word 炸弹 (zhàdàn) is formed by combining two characters: 炸, which means to explode or burst, and 弹, which denotes a bullet, projectile, or ball-shaped object. The concept is built by directly linking the action (exploding) with the physical object (a projectile) to create the composite idea of an "explosive projectile", or a bomb. It is a logical, almost pictorial compound where the first character describes the function and the second defines the form.