brownie Meaning, Definition & Usage

  1. noun a junior Girl Scout
  2. noun (folklore) fairies that are somewhat mischievous
    gremlin; hob; elf; pixie; imp; pixy.
  3. noun square or bar of very rich chocolate cake usually with nuts

WordNet

Brown"ie noun
Etymology
So called from its supposed tawny or swarthy color.
Definitions
  1. An imaginary good-natured spirit, who was supposed often to perform important services around the house by night, such as thrashing, churning, sweeping. Scot.

Webster 1913