Lalaith means 'laughter' in Sindarin.

The second child and first daughter of Húrin Thalion and Morwen Eledhwen (the last Lord and Lady of Dor-lómin). Lalaith was loved by her brother Túrin. When she was three years old she died from a plague brought from Angband on the wind.

A stream that flowed into Dor-lómin and past the house of Húrin was given the name Nen Lalaith because of her.