) A unit of computation in a quantum computer. The "bit" in qubit is somewhat misleading, although when a qubit is read, it does collapse into a 0 or 1. However, for computation and prior to being observed, the qubit can be in a superposition state, which means multiple states at the same time measured by electron motion and direction.
Unlike classical bits, qubits are not used for storage. Data are transferred to the qubits for computation and then read out for answers. Rather than a charge or pulse of electricity in a bit, it is the electrons in the qubit that are manipulated based on the laws of quantum mechanics.
In addition, while a classical bit is made of transistors, there are different qubit designs and constructions. See quantum computing