Veinlet

noun

1. A small or secondary vein, as on the wing of an insect.
2. A small vein; a venous radicle uniting with another to form a vein; a venule.
3. In entomology, one of the secondary or lesser veins of the wings: same as nervule. See vein, n., 3.
4. In botany, a small vein; one of the ultimate or smaller ramifications of a vein or rib; a nerville.
5. A small vein.