Source : Webster's Revised Unabridged Dictionary (1913)

Waterwort \Wa"ter*wort`\, n. (Bot.)
   Any plant of the natural order {Elatine[ae]}, consisting of
   two genera ({Elatine}, and {Bergia}), mostly small annual
   herbs growing in the edges of ponds. Some have a peppery or
   acrid taste.