The word 十三 (shísān), meaning "thirteen", is formed through the standard Chinese decimal system of numeral construction, where the base unit 十 (ten) is combined directly with the digit 三 (three) in an additive and logical sequence. Unlike English, where "thirteen" inverts the order of the units and tens, Chinese builds numbers transparently: "ten-three" signifies ten plus three. This pattern applies consistently for numbers 11 through 19, making the formation both systematic and intuitive, directly reflecting the mathematical value of the sum of its parts.