leaving no footprints as he passed; but in the waybread of the Elves he found all the sustenance that he needed, and he could sleep, if sleep it could be called by Men, resting his mind in the strange paths of elvish dreams, even as he walked open-eyed in the light of this world.
There are no more uses of "sustenance" in the book.
Show samples from other sources
The soup kitchen was her only sustenance.
As they grew more affluent, gardeners planted more for beauty than for sustenance.