Which metric prefix represents 1 x 10^-3?

The metric prefix that represents 1 x 10^-3 is "Milli." This prefix is derived from the Latin word "mille," meaning thousand, and it is used in the metric system to denote one thousandth of a unit. For instance, one millimeter is equal to one thousandth of a meter, which illustrates the conversion of milli to its corresponding decimal notation.

Understanding the other prefixes can give additional context to why "Milli" is correct. "Micro" represents 1 x 10^-6 and is a smaller fraction, while "Nano" corresponds to 1 x 10^-9, being even smaller. "Centi" stands for 1 x 10^-2, which is a larger fraction than milli. Hence, "Milli" precisely signifies one thousandth, aligning with the provided metric of 1 x 10^-3.