|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|1.||Ernst Werner von (ɛrnst ˈvɛrnər fɔn). 1816--92, German engineer, inventor, and pioneer in telegraphy. Among his inventions are the self-excited dynamo and an electrolytic refining process|
|2.||his brother, Sir William, original name Karl Wilhelm Siemens. 1823--83, British engineer, born in Germany, who invented the open-hearth process for making steel|
siemens sie·mens (sē'mənz)
n. pl. siemens
A unit of electrical conductance in the International System of Units, equal to one ampere per volt.