The word 认定 is formed through the complementary fusion of its two constituent characters: 认 (rèn), which carries the core idea of "recognizing" or "acknowledging" a fact or truth, and 定 (dìng), which conveys the sense of "fixing", "settling", or "making definite". Together, they create a single, unified concept where the process of mental recognition or acceptance is brought to a conclusive and settled state, thus forming the meaning "to firmly believe", "to conclude", or "to set as definitive". It is a semantic compound where the second character intensifies and completes the action of the first.