D defs.my
Entry 1 sense Webster, 1913

Nervation

/(nẽr*vā"shŭn)/ · Ner·va·tion · IPA
01 n. The arrangement of nerves and veins, especially those of leaves; neuration.
  1. 1.
    The arrangement of nerves and veins, especially those of leaves; neuration.
    “The outlines of the fronds of ferns, and their nervation, are frail characters if employed alone for the determination of existing genera.” — J. D. Hooker.