Where does “aquitanus” come from?

aquitanus (Latin) comes from Latin Aquitania, from Latin aqua, from Proto-Italic akʷā, from Proto-Indo-European h₂ekʷeh₂ — water, flowing water.

aquitanus (Latin): Aquitanian

Definitions

Step	Language	Word	Meaning
1	Latin	Aquitania	—
2	Latin	aqua	water
3	Proto-Italic	akʷā	water
4	Proto-Indo-European	h₂ekʷeh₂	water, flowing water

aquitanus — Etymology, Origin & Word History | Etymology Explorer