Rue \Rue\, n. [F. rue, L. ruta, akin to Gr. ?; cf. AS. r?de.] 1. (Bot.) A perennial suffrutescent plant ({Ruta graveolens}), having a strong, heavy odor and a bitter taste; herb of grace. It is used in medicine. [1913 Webster] Then purged with euphrasy and rue The visual nerve, for he had much to see. --Milton. [1913 Webster] They [the exorcists] are to try the devil by holy water, incense, sulphur, rue, which from thence, as we suppose, came to be called herb of grace. --Jer. Taylor. [1913 Webster] 2. Fig.: Bitterness; disappointment; grief; regret. [1913 Webster] {Goat's rue}. See under {Goat}. {Rue anemone}, a pretty springtime flower ({Thalictrum anemonides}) common in the United States. {Wall rue}, a little fern ({Asplenium Ruta-muraria}) common on walls in Europe. [1913 Webster]