The word 诊断 (zhěnduàn, "to diagnose") is formed by combining two conceptual actions into a single, seamless process. The first character, 诊, carries the core meaning of to examine or investigate (as a doctor does a patient). The second, 断, means to judge, decide, or conclude. Therefore, the compound visually and conceptually represents the complete act of "examining and then determining", capturing the very essence of moving from observation to a definitive conclusion, as if seeing through a problem to its root cause.