Source : Webster's Revised Unabridged Dictionary (1913)

Viscin \Vis"cin\, n. (Chem.)
   A clear, viscous, tasteless substance extracted from the
   mucilaginous sap of the mistletoe ({Viscum album}), holly,
   etc., and constituting an essential ingredient of birdlime.

Source : WordNet®

Viscum album
     n : Old World parasitic shrub having branching greenish stems
         with leathery leaves and waxy white glutinous berries;
         the traditional mistletoe of Christmas [syn: {mistletoe},
          {Old World mistletoe}]