An accumulation of goods, generally jewels and precious metals but sometimes including weaponry and clothing, gathered up by creatures that, could not make them themselves, generally had no use for them and could not bear to part with them.
The most common hoards in Middle-Earth were accumulated by Barrow-Wights, Dragons and Trolls. These hoards generally consisted of ill-gotten goods and were kept hidden away in caves or lairs to be shared with, and seen by, no-one.

It could be argued that Elf Kingdoms and Dwarf Kingdoms often had hoards of precious goods , but it would be more correct to call them treasuries as their goods were generally made , or purchased by they themselves, and they would, very reluctantly in the case of Dwarves, spend from their treasuries when needed.