The rook (/rʊk/; ♖, ♜) is a piece in the game of chess. It may move any number of squares horizontally or vertically without jumping, and it may capture an enemy piece on its path; additionally, it may participate in castling. Each player starts the game with two rooks, one in each corner on their own side of the board.

Formerly, the rook (from Persian رخ rokh/rukh, meaning "chariot")^[1][2][3] was alternatively called the tower, marquess, rector, and comes (count or earl).^[4] The term "castle" is considered to be informal or old-fashioned.^[5][6]

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h Starting positions of the rooks

a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h The white rook can move to any square marked with a white dot. The black rook can move to squares with a black dot, or it can capture the white pawn on e7.

The white rooks start on the squares a1 and h1, while the black rooks start on a8 and h8. The rook moves horizontally or vertically, through any number of unoccupied squares. The rook cannot jump over pieces. The rook may capture an enemy piece by moving to the square on which the enemy piece stands, removing it from play. The rook also participates with the king in a special move called castling, wherein it is transferred to the square crossed by the king after the king is shifted two squares toward the rook.

In the medieval shatranj, the rook symbolized a chariot. The Persian word rukh means "chariot",^[14] and the corresponding piece in the original Indian version, chaturanga, has the name ratha (meaning "chariot"). In modern times, it is mostly known as हाथी (elephant) to Hindi-speaking players, while East Asian chess games such as xiangqi and shogi have names also meaning chariot (車) for the same piece.^[15]

Persian war chariots were heavily armored, carrying a driver and at least one ranged-weapon bearer, such as an archer. The sides of the chariot were built to resemble fortified stone work, giving the impression of small, mobile buildings, causing terror on the battlefield.^{[citation needed]}

In Europe, the castle or tower appears for the first time in the 16th century in Vida's 1550 Ludus Scacchia, and then as a tower on the back of an elephant. In time, the elephant disappeared and only the tower was used as the piece.^[16]

In the West, the rook is almost universally represented as a crenellated turret. The piece is called torre ("tower") in Italian, Portuguese, Catalan and Spanish; tour in French; toren in Dutch; Turm in German; torn in Swedish; and torni in Finnish. In Hungarian, it is bástya ("bastion") and in Hebrew ,it is called צריח (tsriʾaḥ, meaning "turret").^[17] In the British Museum's collection of the medieval Lewis chess pieces, the rooks appear as stern warders, or wild-eyed berserker warriors.

Rooks are usually similar in appearance to small castles; thus, a rook is sometimes called a "castle",^[18] though modern chess literature rarely, if ever, uses this term.^[19]

In some languages, the rook is called a ship: Thai เรือ (reūa), Armenian Նավակ (navak), Russian ладья (ladya), Javanese ꦥꦿꦲꦸ (prahu). This may be because of the use of an Arabic style V-shaped rook piece, which some may have mistaken for a ship.^{[20][21][22][23]} It is possible that the rendition comes from Sanskrit roka (ship); however, no chaturanga pieces were ever called a roka. Murray argued that the Javanese could not visualize a chariot moving through the jungles in sweeping fashion as the rook. The only vehicle that moved in straight fashion was ship, thus they replaced it with prahu. Murray, however, did not give an explanation of why the Russians call the piece a "ship".^[23]

Peter Tyson suggests that there is a correlation between the name of the piece and the word rukh, a mythical giant bird of prey from Persian mythology.^[24]

In South Slavic languages, it is called the "cannon" (Топ, Romanised top).

In Kannada, it is known as ಆನೆ (āāne), meaning "elephant".^[25] This is unusual, as the term for elephant is in many other languages applied to the bishop.^[26]

Chess rooks frequently occur as heraldic charges. Heraldic rooks are usually shown as they looked in medieval chess sets, with the usual battlements replaced by two outward-curving horns. They occur in arms from around the 13th century onwards.

In Canadian heraldry, the chess rook is the cadency mark of a fifth daughter.

Unicode defines three codepoints for a rook:

♖ U+2656 White Chess Rook

♜ U+265C Black Chess Rook

🨂 U+1FA02 Neutral Chess Rook

• Rook and pawn versus rook endgame
• Tarrasch rule – rooks belong behind passed pawns
• Lucena position – winning position
• Philidor position – drawing position