The Collaborative International Dictionary of English v.0.48:

Evergreen \Ev"er*green\, n.
   1. (Bot.) An evergreen plant.
      [1913 Webster]

   2. pl. Twigs and branches of evergreen plants used for
      decoration. "The funeral evengreens entwine." --Keble.

The Collaborative International Dictionary of English v.0.48:

Evergreen \Ev"er*green\a. (Bot.)
   Remaining unwithered through the winter, or retaining
   unwithered leaves until the leaves of the next year are
   expanded, as pines cedars, hemlocks, and the like.
   [1913 Webster]

WordNet (r) 3.0 (2006):

evergreen
    adj 1: (of plants and shrubs) bearing foliage throughout the
           year [ant: deciduous]
    n 1: a plant having foliage that persists and remains green
         throughout the year [syn: evergreen, evergreen plant]
         [ant: deciduous plant]