The Collaborative International Dictionary of English v.0.48:

Eglantine \Eg"lan*tine\, n. [F. ['e]glantine, fr. OF. aiglent
   brier, hip tree, fr. (assumed) LL. acuculentus, fr. a dim. of
   L. acus needle; cf. F. aiguille needle. Cf. Aglet.] (Bot.)
   (a) A species of rose (Rosa Eglanteria), with fragrant
       foliage and flowers of various colors.
   (b) The sweetbrier (R. rubiginosa).
       [1913 Webster]

   Note: Milton, in the following lines, has applied the name to
         some twining plant, perhaps the honeysuckle.
         [1913 Webster]

               Through the sweetbrier, or the vine,
               Or the twisted eglantine.          --L'Allegro,
                                                  47.
         "In our early writers and in Gerarde and the
         herbalists, it was a shrub with white flowers." --Dr.
         Prior.
         [1913 Webster]

WordNet (r) 3.0 (2006):

eglantine
    n 1: Eurasian rose with prickly stems and fragrant leaves and
         bright pink flowers followed by scarlet hips [syn:
         sweetbrier, sweetbriar, brier, briar, eglantine,
         Rosa eglanteria]