Where does “martis” come from?

martis (Extremaduran) comes from Latin Martis dīēs, from Latin Mārs, from Proto-Indo-European -ḱos — -y, -ic.

martis (Extremaduran): Tuesday

Definitions

Step	Language	Word	Meaning
1	Latin	Martis dīēs	—
2	Latin	Mārs	—
3	Proto-Indo-European	-ḱos	-y, -ic

martis — Etymology, Origin & Word History | Etymology Explorer