Definition of arch- in English:

arch-

combining form

  • 1Chief; principal:

    ‘archbishop’
    ‘archdiocese’
    chief, principal, foremost, leading, main, pre-eminent, cardinal, major, prime, premier, elite, star, outstanding, ultra-, super-
    top, highest, greatest, best, first, head
    out-and-out, complete, utter, total
    number-one, numero uno
    View synonyms
    1. 1.1 (in an unfavourable sense) pre-eminent of its kind; out-and-out:
      ‘arch-enemy’
      greatest, leading, foremost, best, finest, chief, outstanding, excellent, distinguished, prominent, eminent, important, major, star, top, top-tier, topmost, famous, renowned, celebrated, illustrious, towering, supreme, superior, exceptional, unrivalled, unsurpassed, unequalled, inimitable, incomparable, matchless, peerless, unmatched, transcendent
      View synonyms

Origin

Via Latin from Greek arkhi-, from arkhos chief.

Pronunciation

arch-

/ɑːtʃ/