Source : Webster's Revised Unabridged Dictionary (1913)

Southernwood \South"ern*wood`\, n. (Bot.)
   A shrubby species of wormwood ({Artemisia Abrotanum}) having
   aromatic foliage. It is sometimes used in making beer.

Source : WordNet®

Artemisia abrotanum
     n : shrubby European wormwood naturalized in North America;
         sometimes used in brewing beer [syn: {southernwood}]