The Collaborative International Dictionary of English v.0.48:

Archi- \Ar"chi-\ [L., archi-, Gr. 'archi-, a prefix which is
   from the same root as 'a`rchein to be first, to begin; 'archh
   the first place, beginning; 'archo`s chief. Cf. AS. arce-,
   erce-, OHG. erzi-, G. erz-.]
   A prefix signifying chief, arch; as, architect,
   archiepiscopal. In (Biol.) and (Anat.) it usually means
   primitive, original, ancestral; as, archipterygium, the
   primitive fin or wing.
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Archi
   a city on the boundary of Ephraim and Benjamin (Josh. 16:2),
   between Bethel and Beth-horon the nether.