microsiemens: micro- + siemens, a millionth of a siemens. Used without a period. A symbol in SI, the International System of Units.

What unit is Umhos?

The unit of measurement for conductivity is expressed in either microSiemens (uS/cm) or micromhos (umho/cm) which is the reciprocal of the unit of resistance, the ohm. The prefix "micro" means that it is measured in millionths of a mho. MicroSiemens and micromhos are equivalent units.

What does μs CM stand for?

The standard unit of measurement for freshwater is microSiemens per centimeter (µS/cm). In U.S. customary units, it is also measured as millimhos per centimeter (mmho/cm).