Here's what I could find out:
The symbol K comes from the Latin word "Kalium" which in turn comes from "alkali."
So I tried Kalimac, Kalessin, Kath (that one is sort of pushing it, though...), The Ka, Alcarillo, Alkanoonion, and Alatar (also pushing it a bit), all to no avail.
Here also is a list I found of the word Potassium in other languages:
Latin: Kalium
Czech: Draslík
Croatian: Kalij
French: Potassium
German: Kalium - s
Italian: Potassio
Norwegian: Kalium
Portuguese: Potássio
Spanish: Potasio
Swedish: Kalium
Probably excessively over-analyzed (
), but maybe it will help someone...