In shogi, a bishop (角行) that has been promoted upon reaching the opponent's camp, gaining the ability to move like a bishop and a king.
When a bishop promotes, it becomes a promoted bishop.
A promoted bishop can move any number of squares diagonally, and also one square orthogonally.
Compound of 成り (promotion, from 成る 'to become') and 角 (abbreviation of 角行 'bishop').