The word 心理 is formed through a conceptual fusion of its two components: 心 (xīn), which represents the "heart" or the core seat of emotion and thought, and 理 (lǐ), which signifies underlying "principle", "reason", or "order". It is not merely a "heart-principle" but a conceptual integration where 理 provides a framework of logic and inherent pattern to the abstract, inner world of 心. This creates a holistic notion of the structured, lawful, and fathomable nature of the inner mind, encompassing both emotional and rational processes as a single, organized entity. Thus, it forms a compound idea pointing to the systematic principles governing the psyche.