nervure

from The Century Dictionary.

• noun In arch.:
• noun Any one of the ribs of a groined vault, but especially that part of a rib which forms one of the sides of a compartment of the groining
• noun A projecting molding, particularly if small and acute-angled in profile. Also called nerve.
• noun In botany, a vein or nerve of a leaf.
• noun In entomology, one of the tubes or tubular thickenings which ramify in an insect's wing: a nerve, vein, or costa proceeding along one of certain definite lines, to strengthen the wing and, through a central hollow, to nourish it.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) One of the nerves of leaves.
• noun (Zoöl.) One of the chitinous supports, or veins, in the wings of insects.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun entomology A vein in the wing of an insect.
• noun botany Any of the veins that form the branching framework of conducting and supporting tissues in a leaf or other plant organ.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun one of the horny ribs that stiffen and support the wing of an insect
• noun any of the vascular bundles or ribs that form the branching framework of conducting and supporting tissues in a leaf or other plant organ