Where does “Cousteau” come from?

Cousteau (French) comes from Middle French cousteau, from Old French custel, from Latin cutellis.

Ancestry of “Cousteau”, step by step

Step	Language	Word	Meaning
1	Middle French	cousteau	knife
2	Old French	custel	—
3	Latin	cutellis	—

Cousteau — Etymology, Origin & Word History | Etymology Explorer