An oath is a vow by word of mouth.
Oath may refer to:
- Oath of Fëanor - The oath taken by Fëanor and his sons in the city of Tirion, swearing in the name of Ilúvatar to never rest until the three Silmarils were in their hands again.
- King Éomer and the new King of Gondor, Elessar (Aragorn), renewed their oath of alliance, and reaffirmed Cirion's grant of Calenardhon to the Rohirrim.
- Oath of Eorl - The oath that the Northmen King Eorl swore to the Rulers of Gondor after they gave him and his people Calenardhon to dwell in, in return for coming to their aid at the Battle of the Field of Celebrant.
- In the Second Age Isildur brought with him a three meter tall stone as a symbol of his lineage and Gondor. He set it on a hill in Erech. He made the local hill tribes swear an oath of loyalty on the stone. The hill tribes broke their oath and were doomed to haunt the place as wraiths. At the end of the Third Age, the heir of Isildur, Aragorn II, came to Erech to hold them to their oath again. This time they held true to their oath and formed the Host of the Dead and helped Aragorn fight the Corsairs of Umbar at Pelargir. (in the movie they fought at the Battle of the Pelennor Fields).