The Collaborative International Dictionary of English v.0.48:

Senecio \Se*ne"ci*o\, n. [L., groundsel, lit., an old man. So
   called in allusion to the hoary appearance of the pappus.]
   (Bot.)
   A very large genus of composite plants including the
   groundsel and the golden ragwort.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ivy \I"vy\, n.; pl. Ivies. [AS. [imac]fig; akin to OHG. ebawi,
   ebah, G. epheu.] (Bot.)
   A plant of the genus Hedera (Hedera helix), common in
   Europe. Its leaves are evergreen, dark, smooth, shining, and
   mostly five-pointed; the flowers yellowish and small; the
   berries black or yellow. The stem clings to walls and trees
   by rootlike fibers.
   [1913 Webster]

         Direct
         The clasping ivy where to climb.         --Milton.
   [1913 Webster]

         Ye myrtles brown, with ivy never sere.   --Milton.
   [1913 Webster]

   American ivy. (Bot.) See Virginia creeper.

   English ivy (Bot.), a popular name in America for the ivy
      proper (Hedera helix).

   German ivy (Bot.), a creeping plant, with smooth, succulent
      stems, and fleshy, light-green leaves; a species of
      Senecio (Senecio scandens).

   Ground ivy. (Bot.) Gill (Nepeta Glechoma).

   Ivy bush. (Bot.) See Mountain laurel, under Mountain.


   Ivy owl (Zool.), the barn owl.

   Ivy tod (Bot.), the ivy plant. --Tennyson.

   Japanese ivy (Bot.), a climbing plant (Ampelopsis
      tricuspidata), closely related to the Virginia creeper.


   Poison ivy (Bot.), an American woody creeper (Rhus
      Toxicodendron), with trifoliate leaves, and
      greenish-white berries. It is exceedingly poisonous to the
      touch for most persons.

   To pipe in an ivy leaf, to console one's self as best one
      can. [Obs.] --Chaucer.

   West Indian ivy, a climbing plant of the genus
      Marcgravia.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Senecio
    n 1: enormous and diverse cosmopolitan genus of trees and shrubs
         and vines and herbs including many weeds [syn: Senecio,
         genus Senecio]