Where does “Zaldivar” come from?

Zaldivar (English) comes from Spanish Zaldívar, from Basque Zaldibar, from Basque ibar, from Proto-Basque *ibar.

Ancestry of “Zaldivar”, step by step

Step	Language	Word	Meaning
1	Spanish	Zaldívar	Zaldibar
2	Basque	Zaldibar	—
3	Basque	ibar	valley
4	Proto-Basque	*ibar	—