The word 引发 is formed by combining two independent characters, each contributing a core action to create a sequential, cause-and-effect meaning. The first character, 引, originally picturing a drawn bow, carries the inherent idea of pulling, leading, or initiating a force. It is paired with 发, which embodies the concept of releasing, sending forth, or causing something to emerge, like an arrow leaving the bow. Together, they form a dynamic conceptual chain where 引 represents the initial act of triggering or drawing out, and 发 represents the subsequent action of unleashing or causing something to happen, metaphorically capturing the entire process from catalyst to consequence in a single compound.