pixie (n.)

also pixy, "a fairy," in the rural parts of England associated with the "fairy rings" of old pastures, where they are supposed to dance by moonlight, c. 1630, a word of obscure origin, perhaps from or related to Swedish dialect pyske "small fairy," but the word's original home ("from Cornwall to Wiltshire and Dorset" - OED) suggests it might be Celtic, from Cornwall. The earliest printed references are in pixy-path "bewilderment," literally "path on which one is led astray by pixies," and pixie-led "lost, bewildered." Pixie-puff (1847) was a species of fungus; pixie-purse is an ovicapsule of a shark, skate, or ray found washed up on the shore.