The word 一块 is formed through the conceptual combination of the numeral 一 (one) with the character 块, which originally denotes a lump, chunk, or piece of a solid substance. This pairing fuses the idea of a single unit with the tangible concept of a solid mass, creating a compound that fundamentally means "one lump" or "one piece". Over time, this concrete meaning expanded metaphorically to function as a general unit of measurement for objects often perceived as chunks (like cake or stone) and, most notably, was adopted as the colloquial term for the basic unit of Chinese currency, the yuan, conceptualizing it as a single standardized piece of value.