BQP is a complexity class in computer science that represents problems solvable by a quantum computer in polynomial time. It stands for "Bounded-error Quantum Polynomial time." This means that a quantum algorithm can find a solution to a problem efficiently, with a high probability of correctness, within a time that scales polynomially with the size of the input. BQP is significant because it helps to understand the power of quantum computing compared to classical computing. While P represents problems solvable in polynomial time by classical computers, BQP includes problems that may be infeasible for classical algorithms but can be efficiently solved using quantum algorithms, such as Shor's algorithm.