открывать vs. открытка
I'd like to know if there's an etymological link between "открывать" ("to open") and "открытка" ("post card").
Yes, there is . A post card is essentially an "open" message that is not sealed inside an envelope.
OK thanks! (In my country, it's not uncommon to send post cards inside envelopes so that's why I didn't catch the Russian meaning behind it ^^)