Source : Webster's Revised Unabridged Dictionary (1913)

Venule \Ven"ule\, n. [L. venula, dim. from vena vein.]
   A small vein; a veinlet; specifically (Zo["o]l.), one of the
   small branches of the veins of the wings in insects.

Source : WordNet®

venule
     n : a minute vein continuous with a capillary [syn: {venula}, {capillary
         vein}]