The centimeter-gram-second electromagnetic unit of conductance; one absiemen is the conductance at which a potential of one abvolt forces a current of one abampere; equal to 10⁹ siemens.

One siemen is the conductance at which a potential of one volt forces a current of one ampere and named for Karl Wilhem Siemens.

Karl Wilhem Siemens (1823-1883) was a German electrical engineer; active in Great Britain as Sir Charles William Siemens; with his brother Ernst, established many early electrical-engineering projects and manufacturing facilities.