- mho, siemens, reciprocal ohm, S - a unit of conductance equal to the reciprocal of an ohm
--1 is a kind of conductance unit
- Siemens, Karl Wilhelm Siemens, Sir Charles William Siemens - engineer who was a brother of Ernst Werner von Siemens and who moved to England (1823-1883)
--2 is a kind of engineer, applied scientist, technologist
- Siemens, Ernst Werner von Siemens - German electrical engineer (1816-1892)
--3 is a kind of electrical engineer