Webster's Revised Unabridged Dictionary · 1913

qubit

qubit (kū"bit) , noun

[Shortened from quantum bit.]

(Information theory) A measure of information, being the information that can be stored in one object that can take a quantum state of 0 or 1. It differs from the classical bit of information theory in that quantum states may assume many intermediate states that are superpositions of the individual discrete states; the quantum states of multiple quantum systems may also be correlated by a phenomenon called entanglement, increasing the complexity of the information storage and retrieval process. See 4th bit, n.
Rules for a Complex Quantum World — Michael A. Nielsen, “Rules for a Complex Quantum World”, Scientific American, Nov. 2002, pp. 67-75