Source : Webster's Revised Unabridged Dictionary (1913)

Ribwort \Rib"wort`\, n. (Bot.)
   A species of plantain ({Plantago lanceolata}) with long,
   narrow, ribbed leaves; -- called also {rib grass}, {ripple
   grass}, {ribwort plantain}.

Source : WordNet®

ribwort
     n : an Old World plantain with long narrow ribbed leaves widely
         established in temperate regions [syn: {English plantain},
          {narrow-leaved plantain}, {ribgrass}, {ripple-grass}, {buckthorn},
          {Plantago lanceolata}]