quantization |
in mathematics, the process of converting a continuous set of values into a discrete set. |

quantum |
an irreducible quantity of energy, such as a photon of light. [3 definitions] |

quantum bit |
a fundamental unit of information in quantum computing that is equivalent to the binary bit used in traditional computing; qubit. Whereas the binary bit can only exist in two states (0 or 1), the quantum bit can exist in three states (0, 1, or 0 and 1 simultaneously). |

quantum jump |
a sudden change in the energy level of an atom or molecule. [2 definitions] |

quantum mechanics |
(used with a sing. or pl. verb) a theory in physics describing the motion of objects in terms of the principles of quantum theory. |

quantum theory |
a theory in physics that energy radiates or is absorbed in discontinuous quantities, each a multiple of indivisible units or quanta. |

quarantine |
the enforced separation of people, animals, goods, or the like from others, so as to prevent the spread of contagious illness. [4 definitions] |

quark |
any of several elementary particles believed to be components of protons, neutrons, and related particles. |

quarrel |
an angry or bitter disagreement or argument. [4 definitions] |

quarrelsome |
tending to quarrel easily or frequently; bad-tempered; argumentative. |

quarrier |
one who quarries stone. |

quarry^{1} |
a large open hole or pit dug for mining stone, marble, gravel, or the like. [3 definitions] |

quarry^{2} |
an animal hunted for food or sport. [2 definitions] |

quarry^{3} |
something that is in the shape of a square or diamond, esp. a tile or small windowpane. |

quarryman |
see "quarrier." |

quart |
in the US, a unit of capacity equal to two pints or 0.9464 liter in liquid measure and two pints or 1.101 liters in dry measure. (abbr.: qt.) [3 definitions] |

quarter |
a fraction equal to one fourth of a whole. [15 definitions] |

quarterback |
in football, the chief offensive player who calls the plays and is the first to receive the ball in most plays. [5 definitions] |

quarter day |
any of the four days of the year that are regarded as beginning a new season or quarter and on which quarterly payments are due. |

quarterdeck |
the rear part of the upper deck of a ship, usu. off limits to all but officers. |

quartered |
divided into four parts. [3 definitions] |