Can't beleive they actually had "PIN IDENTIFICATION NUMBER" written on the display in the movie itself
Think my favorite is The Los Angeles Angels - the the angels angels
https://en.wikipedia.org/wiki/Soviet_(council)#Etymology
Much like Los Angeles, if you translate the words back to their original language they become redundant.
The "union" refers to the union of the socialist republics. You can easily have "soviets" without a union, and you can obviously have a union without soviets.
Source: born in the USSR
Based on what it said the direct translation was I had thought it was weird, but I figured the Wikipedia page would know more than I.