*HourDuration* | *documentation* *Time* unit. 1 hour = 60 minutes | |

**has axiom** (=> (*instance* ?HOUR Hour) (*duration* ?HOUR *HourDuration*))
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**has axiom** (*equal* (*MeasureFn* ?NUMBER *DayDuration*) (*MeasureFn* (*MultiplicationFn* ?NUMBER 24) *HourDuration*))
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**has axiom** (*equal* (*MeasureFn* ?NUMBER *HourDuration*) (*MeasureFn* (*MultiplicationFn* ?NUMBER 60) *MinuteDuration*))
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**is an ***instance* of TimeDuration | |

**is an ***instance* of UnitOfMeasure | |

TimeDuration | **is second ***domain* of age | |

**is second ***domain* of *duration* | |

**is second ***domain* of *frequency* | |

UnitOfMeasure | **is second ***domain* of *MeasureFn* | |

PhysicalQuantity | **is partitioned into** ConstantQuantity, FunctionQuantity | |

ConstantQuantity | **is first ***domain* of *MagnitudeFn* | |

Quantity | **is first ***domain* of *AdditionFn* | |

**is first ***domain* of *DivisionFn* | |

**is first ***domain* of *ExponentiationFn* | |

**is first ***domain* of *greaterThan* | |

**is first ***domain* of *greaterThanOrEqualTo* | |

**is first ***domain* of *lessThan* | |

**is first ***domain* of *lessThanOrEqualTo* | |

**is first ***domain* of *MaxFn* | |

**is first ***domain* of *MinFn* | |

**is first ***domain* of *MultiplicationFn* | |

**is first ***domain* of *ReciprocalFn* | |

**is first ***domain* of *RemainderFn* | |

**is first ***domain* of *RoundFn* | |

**is first ***domain* of *SubtractionFn* | |

Abstract | **is ***disjoint* from Physical | |