Troll

In ancient Norse and Swedish, a troll was a supernatural being, sometimes imagined as a dwarf, sometimes as a giant. It was said to live in caves, hills, and like places.

English word: The word troll persists in English as a small, magical creature, such as the troll who lives under the bridge in "The Three Billy Goats Gruff." Words spelled exactly the same refer to a way of singing, with a full voice, and a way of fishing with a line. Neither of those words have anything to do with the small, magical creature.

Dwarf

From Anglo-Saxon, a dwarf is an animal or plant that is much below the normal size of its species or kin. Dwarves are known in many folk tales, notably "Snow White and the Seven Dwarves." Like gnomes, they do good work for humans if they like the humans.

English word: The word dwarf, and its plural, dwarves, are common in English. They both refer precisely to the Anglo-Saxon root, "an animal or plant that is much below the normal size of its species or kin." The words may refer to an unusually small species of plant or animal, or they may refer to humans born with genes that express as dwarfism.