The Collaborative International Dictionary of English v.0.48:

Nervure \Nerv"ure\ (n[~e]rv"[-u]r), n. [F. See Nerve.]
   1. (Bot.) One of the nerves of leaves.
      [1913 Webster]

   2. (Zool.) One of the chitinous supports, or veins, in the
      wings of insects.
      [1913 Webster]

WordNet (r) 3.0 (2006):

nervure
    n 1: any of the vascular bundles or ribs that form the branching
         framework of conducting and supporting tissues in a leaf or
         other plant organ [syn: vein, nervure]
    2: one of the horny ribs that stiffen and support the wing of an
       insect [syn: vein, nervure]