Nen

nen is a noun meaning "small river, tributary" or "small lake" in Sindarin.

Examples:

• Nen Hithoel = "Lake of Mist"
• Nen Lalaith = "River of Laughter"

References

• The Languages of Tolkien's Middle-earth by Ruth S. Noel
• Hiswelókë's Sindarin Dictionary compiled by Didier Willis