n.
Function: prefix
Etymology: Middle English arche-, arch-, from Old English & Anglo-French; Old English arce-, from Late Latin arch- & Latin archi-; Anglo-French arch-, from Late Latin arch- & Latin archi-, from Greek arch-, archi-, from archein to begin, rule; akin to Greek arch ē beginning, rule, archos ruler
1 : chief : principal < arch fiend>
2 : extreme : most fully embodying the qualities of the kind < arch conservative>