Where does “Sieradzka” come from?

Sieradzka (Polish) comes from Polish Sieradzki, from Polish -zki, from Proto-Slavic -ьskъ, from Proto-Indo-European -iskos — Characteristic of, typical of, pertaining to.

Ancestry of “Sieradzka”, step by step

Step	Language	Word	Meaning
1	Polish	Sieradzki	—
2	Polish	-zki	forms surnames; forms adjectives
3	Proto-Slavic	-ьskъ	-ic, -ish
4	Proto-Indo-European	-iskos	Characteristic of, typical of, pertaining to

Every word from Proto-Indo-European -iskos →Every word from Proto-Slavic -ьskъ →Every word from Polish -zki →