What is the symbol used to represent a nanometer?

The symbol used to represent a nanometer is "nm." A nanometer is one billionth of a meter (10^-9 meters) and is commonly used in fields such as nanotechnology, semiconductor manufacturing, and molecular biology to measure extremely small distances. The prefix "nano-" denotes a factor of 10^-9, which is critical in understanding measurements at the atomic and molecular scale.

In contrast, the other options represent different units of measurement. "mm" stands for millimeter, which is one thousandth of a meter (10^-3 meters), while "μm" represents a micrometer, equal to one millionth of a meter (10^-6 meters). "pm," on the other hand, denotes picometer, which is one trillionth of a meter (10^-12 meters). Each of these units serves specific purposes in various scientific domains, but "nm" is uniquely designated for nanometer measurements.