Quaalude |
trademark for the sedative drug methaqualone. |

quack^{1} |
the sound made by a duck, or a similar sound. [2 definitions] |

quack^{2} |
someone who practices medicine incompetently and often without proper training. [4 definitions] |

quackery |
the claims, methods, or practice of a quack. |

quack grass |
see "couch grass." |

quad^{1} |
a large, open, usu. grassy area with buildings on all four sides, esp. on a college campus; quadrangle. |

quad^{2} |
in printing, a piece of type that does not register, used for filling blank areas and spaces. [2 definitions] |

quad^{3} |
a quadruplet. |

quad^{4} |
quadraphonic. [2 definitions] |

quad^{5} |
a unit of energy equal to one quadrillion British thermal units. |

Quadragesima |
the first Sunday of Lent. |

quadrangle |
a closed two-dimensional figure with four sides, such as a rectangle or parallelogram. [3 definitions] |

quadrant |
one quarter of the arc of a circle. [5 definitions] |

quadraphonic |
of, concerning, or used for the reproduction of sound, esp. music, over four distinct channels. |

quadrat |
see "quad^{2}." [2 definitions] |

quadrate |
a square or rectangle. [5 definitions] |

quadratic |
of, concerning, or involving mathematical expressions containing a variable that is raised to the second power at most. [2 definitions] |

quadratic equation |
in algebra, an equation in which the square is the highest power to which the unknown quantity is raised. |

quadrature |
the act or process of squaring. [3 definitions] |

quadrennial |
happening once every four years. [3 definitions] |

quadri- |
four. |