Name of the grave of Túrin and Nienor (UT/140), a combination of sarch “grave”, the definite plural form nia of the preposition na(n) “of” (also seen in Glaer nia Chîn Húrin), the mutated plural chîn of hên “child” and the name of their father Húrin. The unmutated form Hîn in the Unfinished Tales was an editorial decision by Christopher Tolkien (LR/322 note §25); the name was spelled correctly (with Chîn) in The Children of Húrin (CH/247).
Sindarin
Sarch nia Hîn Húrin
noun. grave of the children of Húrin
sarch nia chîn húrin
proper name. Grave of the Children of Húrin
sarch (“grave”), nia (pre-LR period plural genitive article, later changed to in WJ: hîn (pl. of hên “child”), hûr (“vigour, fiery spirit”) + ind (“inner thought, heart”)