venation noun2. 
[vɪ'neɪʃ(ǝ)n] M17.[from Latin vena vein + -ATION.]1.  The arrangement or structure of sap-vessels in a plant. 
rare. Only in 
M17.2.  Botany & 
Entomology. The arrangement of veins in the leaves of a plant or the wings of an insect. 
M17.  [TahlilGaran] English Dictionary ▲