Term:

Intersecondary vein
Definition:

A leaf vein that is intermediate in size between secondary and tertiary veins and often runs parallel to the infra adjacent and supra adjacent secondary veins bounding it. At about the middle between the midrib and the leaf blade margin, intersecondary veins start to ramify dendritically.
Notes:

In neotropical Lecythidaceae, intersecondary veins are more common among the zygomorphic-flowered genera than they are among the actinomorphic-flowered genera. They may occur in the latter but they are usually not present between all secondary veins and when they are they are less well developed.