The word 镇定 is formed by combining two characters, each contributing a layer of meaning to create a unified concept. The first character, 镇, carries the core idea of suppressing, weighing down, or pacifying, as if settling something restless. The second, 定, means to be stable, fixed, or settled. Together, they sequentially depict the process of first quelling or calming internal agitation (镇) in order to then arrive at a state of composed stability and steadiness (定), forming the complete idea of "calm and composed".