Where does “thermalis” come from?

thermalis (New Latin) comes from Ancient Greek Θέρμη, from Proto-Indo-European gʷʰer-, from Proto-Indo-European gʷʰe-gʷʰór-e ~ gʷʰe-gʷʰr-ḗr.

Ancestry of “thermalis”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Θέρμη	—
2	Proto-Indo-European	gʷʰer-	warm, hot
3	Proto-Indo-European	gʷʰe-gʷʰór-e ~ gʷʰe-gʷʰr-ḗr	—

thermalis — Etymology, Origin & Word History | Etymology Explorer