What is the etymology of the Russian word приставка?
This word is coined (apparently) by Vostokov in his Русская Грамматика, 1830.
Preceding authors, including Gretsch who published Пространная русская грамматика just three years earlier, in 1827, did not differentiate prefixes and prepositions.
The word itself is a not so good calque from Latin "prefix". A more exact term would have been представка which had been in limited use for some time, but has not settled down. The word приставка already existed in Russian by that time with the meaning "appendage, lace", that's probably why it was chosen.
Other similarly formed terms, like "suffix", "infix" etc., had been just borrowed into Russian rather than calqued.