The word 还是 is formed by combining two distinct characters, each with its own core meaning, to create a new, unified concept. The first character, 还 (hái), carries an inherent sense of continuation, repetition, or returning to a previous state. The second, 是 (shì), is a fundamental verb meaning "to be" or "yes", representing affirmation, correctness, or existence. Their fusion metaphorically conveys the idea of "returning to or affirming an alternative option" or "continuing to be the case", which semantically extends to express comparative choice ("or") or persistent state ("still"). Thus, the formation hinges on the conceptual blending of continuity (还) with a state of being (是).