\Rook"er*y\, n.; pl. {Rookeries}. 1. The breeding place of a colony of rooks; also, the birds themselves. --Tennyson. 2. A breeding place of other gregarious birds, as of herons, penguins, etc. 3. The breeding ground of seals, esp. of the fur seals. 4. A dilapidated building with many rooms and occupants; a cluster of dilapidated or mean buildings. 5. A brothel. [Low]