Ivanka is the feamle form of the name “Ivan.”
Will Dreyfus

The name is actually Czech, and an alternate form of “Ivana”, the name of Ivanka’s mother. This isn’t really surprising, considering that Ivanka’s mother is Czech.

You are correct that the root is “Ivan” which is the Russian equivalent of “John”. However, “Ivan” isn’t limited to Russian. It’s also the form of “John” in Czech and Slavic languages.