BQP stands for "Bounded-Error (or Probabilistic) Quantum Polynomial Time". It is a type of mathematical problem that can only be solved by a quantum computer. A quantum computer is a very powerful type of computer that uses quantum physics to store and process information. The main advantage of a quantum computer is that it can solve problems much faster than a regular computer. BQP is a type of problem that only a quantum computer can solve in a short amount of time.