Old Norse álfar = 'elves'
Snorri distinguishes between Ljósálfar (light elves) and Svartálfar = 'black elves'.
The light elves live in Alfheimr which he obviously thought of as a sort of heaven or in Víðbláinn. They are more beautiful than the sunlight.
The black elves live in Svartálfaheimr, and according to Snorri they might be dwarfs.