The Collaborative International Dictionary of English v.0.48:

Broom \Broom\ (br[=oo]m), n. [OE. brom, brome, AS. br[=o]m; akin
   to LG. bram, D. brem, OHG. br[=a]mo broom, thorn?bush, G.
   brombeere blackberry. Cf. Bramble, n.]
   1. (Bot.) A plant having twigs suitable for making brooms to
      sweep with when bound together; esp., the Cytisus
      scoparius of Western Europe, which is a low shrub with
      long, straight, green, angular branches, minute leaves,
      and large yellow flowers.
      [1913 Webster]

            No gypsy cowered o'er fires of furze and broom.
                                                  --Wordsworth.
      [1913 Webster]

   2. An implement for sweeping floors, etc., commonly made of
      the panicles or tops of broom corn, bound together or
      attached to a long wooden handle; -- so called because
      originally made of the twigs of the broom.
      [1913 Webster]

   Butcher's broom, a plant (Ruscus aculeatus) of the Smilax
      family, used by butchers for brooms to sweep their blocks;
      -- called also knee holly. See Cladophyll.

   Dyer's broom, a species of mignonette (Reseda luteola),
      used for dyeing yellow; dyer's weed; dyer's rocket.

   Spanish broom. See under Spanish.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Butcher's broom \Butch"er's broom`\ (Bot.)
   A genus of plants (Ruscus); esp. Ruscus aculeatus, which
   has large red berries and leaflike branches. See
   Cladophyll.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ruscus aculeatus
    n 1: shrub with stiff flattened stems resembling leaves
         (cladophylls); used for making brooms [syn: butcher's
         broom, Ruscus aculeatus]