The word 大约 is formed by combining two characters: 大 (dà), meaning "big" or "great", and 约 (yuē), meaning "to bind" or "agreement". Conceptually, it creates the sense of a "broad agreement" or a "loose binding", where an estimate is not pinned to a precise point but is instead held within a wider, accepted range. This fusion metaphorically represents the idea of approximation, a figure that is generally agreed upon as being close, but not strictly confined.