The word 基础 is formed through a conceptual and metaphorical combination of its two component characters. The first character, 基 (jī), originally depicted the foundation or groundwork of a building, representing the base upon which something is built. The second character, 础 (chǔ), specifically referred to the stone plinth or base beneath a pillar. When combined, they create a compound where both elements reinforce the same core idea of a physical, supportive foundation. This literal meaning of a building's base is then extended metaphorically to form the modern abstract concept of a "foundation", "basis", or "fundamentals" for anything, from knowledge to systems, by blending their concrete, architectural imagery into a single, stronger notion of essential support.