Other forms: runnels
A runnel is a trickle of water finding its own course, or the small groove it wears. A runnel of rain, runnels down the glass, cut a runnel.
It names both the water and the channel, which is convenient because the two are hard to separate. It is a literary word rather than a technical one, and it turns up most often describing rain on a window or sweat on a face.
1nounrunnelA trickle of water finding its own small course.
“After the storm, a runnel of rainwater trickled down the garden path.”
2nounshallowThe shallow groove such a trickle wears.
“Centuries of rain had worn deep runnels into the soft stone steps.”
runnel is a trickle, or a groove.
Old English rynel meant a little stream, from rinnan, to run, with the diminutive ending.
Proto-Germanic
*runilaz
Old English
rynel — that which runs; runner; stream
Middle English
runel
English, today
runnel
From Middle English runel, rennel, rinel, from Old English rynel (“that which runs; runner; stream”), from Proto-Germanic runilaz, equivalent to run + el. Cognate with Scots rinel, rinnal (“stream; runnel”), Swedish rännel (“runner; runnel”).
Etymology from Wiktionary, CC BY-SA