The Chinese word 水准 (shuǐzhǔn) is a compound term formed by combining the characters 水 (shuǐ), meaning "water", and 准 (zhǔn), meaning "level" or "standard". It originated from the concept of a water level, an ancient tool used in construction and surveying to determine a perfectly horizontal plane, as water naturally finds its own level. By metaphorical extension, this concrete tool for measuring physical flatness evolved to represent an abstract standard, quality, or benchmark in various fields, such as artistic, academic, or technical performance. Thus, the term captures the idea of a fixed reference point or degree of excellence, much like the invariant horizon line established by water.