The word Doom is often used by Tolkien in its old sense of a final judgement or settled fate, as in the 'Doom of Mandos' or the 'Doom of Men'. There is only a single case of the word being used as a capitalised noun without qualification, and that relates to the curse of dark fate that Morgoth placed on the kin of Húrin Thalion.

Morgoth sought to discover where Gondolin lay from Húrin, whom he had captured in the Nirnaeth, but Húrin refused him. In punishment Morgoth imprisoned Húrin high in the peaks of Thangorodrim, forcing him to watch over Beleriand, as a terrible curse worked on Húrin's family. It was this Doom that followed Húrin's son Túrin throughout his life, and it also enmeshed his daughter Niënor. Ultimately the working of the Doom caused both of these Children of Húrin to take their own lives.