Borrowed from German SED (“Sozialistische Einheitspartei Deutschlands”).
Meanings
(historical) The Socialist Unity Party.
In an interview with Jacobin to be published later this year, veteran KPO activist Theodor Bergmann tells of Heinrich Adam, prewar KPO member and mechanic at the Zeiss optics factory in Jena who joined the SED in hopes of realizing socialist unity. 2017 May 14, Loren Balhorn, “The Lost History of Antifa”, in Jacobin Magazine: