brownie

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A member of the Girl Scouts from six through eight years of age.
• noun A bar of moist, usually chocolate cake, often with nuts.
• noun A small sprite thought to do helpful work at night.
• noun A brown trout.

from The Century Dictionary.

• noun In Scotland, a spirit supposed to haunt houses, particularly farm-houses.

from the GNU version of the Collaborative International Dictionary of English.

• noun Scot. An imaginary good-natured spirit, who was supposed often to perform important services around the house by night, such as thrashing, churning, sweeping.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A small square piece of rich cake, usually made with chocolate.
• noun folklore A mythical creature, a helpful elf who would do people′s housework for them.
• noun paganism A household spirit or revered ancestor.
• noun Australia, New Zealand (colloquial) A tall, long-necked beer bottle, made from brown coloured glass.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (folklore) fairies that are somewhat mischievous
• noun square or bar of very rich chocolate cake usually with nuts
• noun a junior Girl Scout