This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
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n. A building separate from but associated with a main building.

n. A building, such as a barn, shed, or garage, that is separate from, but associated with some main building

n. A building separate from, and subordinate to, the main house; an outhouse.

n. A building near or subordinate to a main building; an outhouse.

n. a building that is subordinate to and separate from a main building

"What remained of the outbuilding was a heap of redstone, discolored by soot and ashes."

building    edifice   

outhouse   

remise    doghouse    dog house    garage    outhouse    earth-closet    carriage house    coach house    jakes    shed   

outhouse   

outbuild   

posthouse    gharry    market-cart    freq    boathouse    emblazonry    henhouse    place    war-work    pulverization