Where does “Chelm” come from?

Chelm (Portuguese) comes from Polish Chełm, from Proto-Slavic xъlmъ, from Proto-Germanic hulmaz, from Proto-Indo-European kl̥Hmos, from Proto-Indo-European ḱelH- — to freeze.

Ancestry of “Chelm”, step by step

StepLanguageWordMeaning
1PolishChełm—
2Proto-Slavicxъlmъhill
3Proto-Germanichulmazsmall island, hill, mound
4Proto-Indo-Europeankl̥Hmos—
5Proto-Indo-EuropeanḱelH-to freeze
Every word from Proto-Indo-European ḱelH- →Every word from Proto-Indo-European kl̥Hmos →Every word from Proto-Germanic hulmaz →