Real Dictionary

rook
countable noun: A rook is a large black bird. Rooks are members of the crow family.
countable noun: In chess, a rook is one of the chess pieces which stand in the corners of the board at the beginning of a game. Rooks can move forwards, backwards, or sideways, but not diagonally.

rook in American English 1
a gregarious European crow (Corvus frugilegus) with a bare spot by its bill
to swindle, cheat, defraud, etc.
noun: a black, European crow, Corvus frugilegus, noted for its gregarious habits
transitive verb: to cheat; fleece; swindle

rook in American English 2
either of the two corner pieces shaped like a castle tower: it can move in a vertical or horizontal direction only over any number of consecutive, unoccupied squares; castle
noun: one of two pieces of the same color that may be moved any number of unobstructed squares horizontally or vertically; castle

rook in British English 1
noun: a large Eurasian passerine bird, Corvus frugilegus, with a black plumage and a whitish base to its bill: family Corvidae (crows)
verb: to overcharge, swindle, or cheat

rook in British English 2
noun: a chesspiece that may move any number of unoccupied squares in a straight line, horizontally or vertically