SEIDL - southern German: from a pet form of the personal name "Siegfried". (Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4)
Siegfried German: from a Germanic personal name composed of the elements sigi ‘victory’ + fridu ‘peace’. The German surname has also occasionally been adopted by Ashkenazic Jews. (Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4)