The stabilizer rank of a pure quantum state is defined as the smallest integer m such that it can be expressed as a superposition of m stabilizer states. Combined with the magic states introduced by Bravyi and Kitaev, such a notion becomes especially useful because one can analyze the complexity of circuits composed of Clifford+T gates in terms of the stabilizer rank of the magic input state, which can be taken to be m tensor factors of the T magic state. References: arXiv:1506.01396