nervure \NUR-vyoor\, noun:

nervure \NUR-vyoor\, noun:

A vein, as of a leaf or the wing of an insect.

It was a sorrel, between three and four years old, tall, svelte, with a straight back, a belly tight with muscles, thin legs wrapped up in a vigorous nervure and a small head.
-- Francisco Coloane, Cape Horn and Other Stories from the End of the World
We walked along a corridor affected by the regular spacing of the trees, beneath a sort of dais for which the framework was made of delicate leaf nervure.
-- J. H. Matthews, The Custom-House Of Desire: A Half-Century of Surrealist Stories
Nervure is French for "rib."