Where does “interhelical” come from?

interhelical (English) comes from English inter-, from Latin inter- — inter-.

interhelical (English): Between helices, especially between the helices...

Definitions

Step	Language	Word	Meaning
1	English	inter-	between, amid, among, during, within, mutual,...
2	Latin	inter-	inter-

interhelical — Etymology, Origin & Word History | Etymology Explorer