Where does “Thessalonica” come from?

Thessalonica comes from Ancient Greek Θεσσᾰλονῑ́κη, a place name of uncertain ultimate origin.

Ancestry of “Thessalonica”, step by step

Step	Language	Word	Meaning
1	Latin	Thessalonīca	—
2	Ancient Greek	Θεσσαλονίκη	Thessaloníkē
3	Ancient Greek	Νῑ́κη	—
4	Ancient Greek	νῑ́κη	conquered; victory

Thessalonica — Etymology, Origin & Word History | Etymology Explorer