Which battle in Tolkien’s legendarium is also called Nirnaeth Arnoediad?

Nirnaeth Arnoediad is the Elvish name for the Battle of Unnumbered Tears. It is one of the great battles described in the First Age history of Tolkien’s legendarium.

The battle was fought in Beleriand between the forces of the Elves and their allies and the armies of Morgoth. The planned alliance suffered betrayal and military disaster, and the defeat caused devastating consequences for the kingdoms opposing Morgoth. Its name refers to the immense grief that followed.

The battle is most closely associated with The Silmarillion and the stories of the First Age, not with the events of The Lord of the Rings. It also appears in related versions of Tolkien’s legendarium, including narratives concerning Túrin Turambar and the fall of Nargothrond. “Nirnaeth Arnoediad” is a Sindarin phrase, while the English title provides the same event’s common translation.