W state
The W state is an entangled quantum state of three qubits which has the following shape
and which is remarkable for representing a specific type of multipartite entanglement and for occurring in several applications in quantum information theory. Particles prepared in this state reproduce the properties of Bell's Theorem which states that no classical theory of hidden variables can ever produce the predictions of quantum mechanics.
The W state is the representative of one of the two non-biseparable classes of three-qubit states (the other being the GHZ state) which cannot be transformed (not even probabilistically) into each other by local quantum operations. Thus and represent two very different kinds of tripartite entanglement.
...
Wikipedia