arch- 1
a combining form that represents the outcome of archi- in words borrowed through Latin from Greek in the Old English period; it subsequently became a productive form added to nouns of any origin, which thus denote individuals or institutions directing or having authority over others of their class ( archbishop; archdiocese; archpriest ). More recently, arch- 1 has developed the senses "principal" ( archenemy; archrival ) or "prototypical" and thus exemplary or extreme ( archconservative ); nouns so formed are almost always pejorative.
[ ME; OE arce-, aerce-, erce- ( > ON erki- ) archi- aarts-, MLG erse-, MHG, G Erz- arci-, and Goth ark- directly ]
arch- 2
var. of archi- before a vowel: archangel; archenteron.