Source : Webster's Revised Unabridged Dictionary (1913)

Isatis \I"sa*tis\ (?; 277), n. [L., a kind of plant, Gr. ?
   woad.] (Bot.)
   A genus of herbs, some species of which, especially the
   {Isatis tinctoria}, yield a blue dye similar to indigo; woad.

Source : WordNet®

Isatis
     n : Old World genus of annual to perennial herbs: woad [syn: {genus
         Isatis}]