Source : Webster's Revised Unabridged Dictionary (1913)

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.

            Then purged with euphrasy and rue The visual nerve,
            for he had much to see.               --Milton.

            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.

   2. Fig.: Bitterness; disappointment; grief; regret.

   {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.

Source : WordNet®

Ruta graveolens
     n : European strong-scented perennial herb with gray-green
         bitter-tasting leaves; an irritant similar to poison ivy
         [syn: {rue}, {herb of grace}]