archi-

WordReference Random House Unabridged Dictionary of American English © 2025

archi-, 

1. a combining form with the general sense "first, principal,'' that is prefixed to nouns denoting things that are earliest, most basic, or bottommost (archiblast;
   archiphoneme;
   architrave);
   or denoting individuals who direct or have authority over others of their class, usually named by the base noun (archimandrite;
   architect).
Also,[esp. before a vowel,] arch-. Cf. arch- ¹ , arche-. 
• Greek, combining form akin to arché̄ beginning, árchos leader, árchein to be the first, command

Collins Concise English Dictionary © HarperCollins Publishers::

archi- combining_form

1. a variant of arch-

Collins Concise English Dictionary © HarperCollins Publishers::

arch-, archi- combining_form

1. chief; principal; of highest rank
2. eminent above all others of the same kind; extreme

Etymology: ultimately from Greek arkhi-, from arkhein to rule