WordReference Random House Unabridged Dictionary of American English © 2024quan′tum num′ber, [Physics.]- Physicsany integer or half of an odd integer that distinguishes one of the discrete states of a quantum-mechanical system.
- Physicsany number that distinguishes among different members of a family of elementary particles.
Collins Concise English Dictionary © HarperCollins Publishers::
quantum number n - one of a set of integers or half-integers characterizing the energy states of a particle or system of particles. A function of the number multiplied by a fixed quantity gives the observed value of some specified physical quantity possessed by the system