Nen Lalaith

Nen Lalaith was a babbling stream that rose under the mountain of Amon Darthir in the Mountains of Shadow, and flowed northwestwards out onto the shaded plains of Dor-lómin. There, it trickled past the house of Húrin, and was said to have given its name to his ill-fated young daughter, Lalaith.

Etymology

Nen Lalaith means "River of Laughter" in Sindarin (from nen = "river, water" and lalaith = "laughter").