| Roccellic | a. [ F. roccellique, fr. roccelle archil, It. & NL. roccella, fr. It. rocca a rock, because archil grows on rock. ] (Chem.) Pertaining to, or designating, a dibasic acid of the oxalic series found in archil (Roccella tinctoria, etc.), and other lichens, and extracted as a white crystalline substance |