The Collaborative International Dictionary of English v.0.48:

Espalier \Es*pal"ier\, v. t. [imp. & p. p. Espaliered; p. pr.
   & vb. n. Espaliering.]
   To form an espalier of, or to protect by an espalier.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Espalier \Es*pal"ier\, n. [F. espalier, fr. It. spalliera, fr.
   spalla shoulder, the same word as F. ['e]paule. See
   Epaulet.] (Hort.)
   A railing or trellis upon which fruit trees or shrubs are
   trained, as upon a wall; a tree or row of trees so trained.
   [1913 Webster]

         And figs from standard and espalier join. --Pope.
   [1913 Webster]

WordNet (r) 3.0 (2006):

espalier
    n 1: a trellis on which ornamental shrub or fruit tree is
         trained to grow flat