The Presidium of the Supreme Soviet (Russian: Президиум Верховного Совета or Prezidium Verkhovnogo Soveta) was a Soviet governmental institution. It was a permanent body of the Supreme Soviets (parliaments).
The Soviet Republics' (SSRs') soviets (English: literally "Council") met infrequently (often only twice a year and then for only several days). They would also elect the Presidium of the Supreme Soviet, as a permanent body, to act on their behalf while the soviet was not in session.
The union wide national equivalent elected by the The Supreme Soviet of the Soviet Union.
A presidium or praesidium (English plural presidiums or pr(a)esidia) comes from the Russian: prezidium, that is from Latin: praesidium, which is derived from the Latin word "praesidēre", meaning "to superintend"/"to preside" [it is linguisticly related to "president"].