Lindow states that the etymology of the word "troll" remains uncertain, though he defines trolls in later Swedish folklore as "nature beings" and as "all-purpose otherworldly being[s], equivalent, for example, to fairies in Anglo-Celtic traditions". They "therefore appear in various migratory legends where collective nature-beings are called for". Lindow notes that trolls are sometimes swapped out for cats and "little people" in the folklore record.[10]