The unit Siemens is of a physical quantity 

The term “Siemen is the unit of” conductance, which represents how efficiently electric current flows through a material. Conductance is a fundamental concept in electrical engineering and physics, as it indicates the ease with which electrons move within a conductor or even certain non-conducting materials.

Conductance, symbolized by the capital letter "G," is inversely related to resistance, meaning that higher conductance corresponds to lower resistance. The standardized unit of conductance is the Siemen, abbreviated as (S). This unit was formerly referred to as “mho,” which is the reverse spelling of “ohm,” the unit for resistance.

The Siemen is the unit of choice for measuring conductance because it directly relates to the ability of a material to facilitate the flow of electric current. Whether metals or nonmetals, materials that allow current to flow with minimal resistance exhibit high conductance, measurable in Siemens.

In summary, Siemen is the unit of conductance, making it an essential metric in understanding electrical properties. It is widely used in various scientific and engineering applications to quantify and analyze how well electricity moves through a substance. The use of Siemens as the standardized measurement ensures consistency and accuracy in calculations and experiments related to electrical conductance.