Fëa and hröa

fëa and hröa are words for "soul" (or "spirit") and "body". The plural form of fëa is fëar (pronounced []) and the plural form of hröa is hröar (pronounced []).

The Children of Ilúvatar (Elves and Men) are described as existing as two parts: they have a "spirit" or "soul" called fëa which comes from the Secret Fire of Ilúvatar, and a body or hröa which is made out of Arda. According to the Elves, the fëa is powerless without the hröa, and likewise the hröa would die without the fëa.

The Elves' fate is to live as long as Arda exists; they are bound to the world and cannot leave it. Unlike Men, Elves do not die of disease or of old age. However, Elves may be slain or lose the will to live, for instance because of grief. When an Elf dies, the fëa leaves the hröa, which then "dies". The fëa is called to the Halls of Mandos, where it is judged. If allowed by Mandos, the fëa may be reincarnated into a new-born body that is identical to the previous hröa.

A fëa may decide to stay in Mandos, or it may be denied reincarnation, for example if it had done much evil. In such a case the fëa might have to wait very long or might never be allowed to leave Mandos.

The situation of Men is different: a Mannish fëa is only a visitor to Arda, and when the hröa dies, the fëa leaves Arda completely.

For this reason it is said the Fates of Men and Elves are sundered. The choice of the Half-elven is one of the fëa, not of the hröa. Lúthien chose the Fate of Men, and so her fëa passed out of Arda and was lost to her kin.

Not only the Children of Ilúvatar possessed fëa: they were also granted to the Ents and some animals, such as Huan the Hound and the great Eagles (but see the end of that article). When Ilúvatar adopted Aulë's children, the Dwarves, he granted them, too, fëa of their own.

Celtic goddess
There is also an Irish goddess by the name Fea. Apparently, her name derives from proto-Celtic for "woe", an appropriate name as she is sometimes counted among the names of the Morrígan.