- a small stream; brook; rivulet.
- a small channel, as for water.
"rivulet," 1577, in Hakluyt, from O.E. rinelle, a dim. form related to rinnan "to run" (see run (v.)).
"Dribbling down some of the tree trunks were little runnels that looked like dried sap. On a previous visit to the Amazon I had seen runnels just like these on a rubber tree in an abandoned plantation. Thinking it was a drip of latex sap, I plucked at one."
- Charles Mann, 1491: New Revelations of the Americas Before Columbus