*SecondDuration* | *documentation* SI TimeDuration. Symbol: s. It is one of the base units in SI, *and* it is currently defined as follows: the *SecondDuration* is the *duration* of 9192631770 periods of the radiation corresponding to the transition *between* the two hyperfine levels of the ground state of the cesium 133 atom | |

**has axiom** (=> (*instance* ?SECOND Second) (*duration* ?SECOND *SecondDuration*))
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**has axiom** (*equal* (*MeasureFn* ?NUMBER *MinuteDuration*) (*MeasureFn* (*MultiplicationFn* ?NUMBER 60) *SecondDuration*))
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**has axiom** (*equal* (*MeasureFn* ?NUMBER *PicoSecond*) (*MeasureFn* (*MultiplicationFn* ?NUMBER 1.0E-12) *SecondDuration*))
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**is first ***domain* of *CoulombFn* | |

**is an ***instance* of SystemeInternationalUnit | |

**is an ***instance* of TimeDuration | |

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

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

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

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

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