Webster's Revised Unabridged Dictionary · 1913

Archil

Archil (?; 277) , noun

[Old French orchel, orcheil, Italian orcella, oricello, or OSp. orchillo. Compare 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.