Where does “diaconal” come from?

diaconal (Middle French) comes from Latin diāconus, from Ancient Greek διᾱ́κονος — servant, minister.

Ancestry of “diaconal”, step by step

Step	Language	Word	Meaning
1	Latin	diāconus	—
2	Ancient Greek	διᾱ́κονος	servant, minister

diaconal — Etymology, Origin & Word History | Etymology Explorer