Where does “campio” come from?

campio (Late Latin) comes from Frankish kampijō, from Proto-Germanic kampijô, from Latin campus, from Proto-Indo-European kh₂emp-, from Proto-Indo-European kh₂em- — to bend, to curve.

Ancestry of “campio”, step by step

Step	Language	Word	Meaning
1	Frankish	kampijō	fighter; combat soldier
2	Proto-Germanic	kampijô	—
3	Latin	campus	Open flat level ground: a plain, a natural field;...
4	Proto-Indo-European	kh₂emp-	to bend; crooked; to bend, curve
5	Proto-Indo-European	kh₂em-	to bend, to curve

Every word from Proto-Indo-European kh₂em- →Every word from Proto-Indo-European kh₂emp- →Every word from Latin campus →