What does archil mean?
The definition of archil
Ar”chil, n.
Etym: [OF. orchel, orcheil, It. orcella, oricello, or OSp. orchillo. Cf. Orchil.]

1 A violet dye obtained from several species of lichen (Roccella tinctoria, etc.), which grow on maritime rocks in the Canary and Cape Verd Islands, etc. Tomlinson.
2 The plant from which the dye is obtained. [Written also orchal and orchil.]