# A CDE Definition

numerical aperture

The measurement of the acceptance angle of an optical fiber, which is the maximum angle at which the core of the fiber will take in light that will be contained within the core. Taken from the fiber core axis (center of core), the measurement is the square root of the squared refractive index of the core minus the squared refractive index of the cladding. See critical angle and fiber optics glossary.

**The Acceptance Angle**

**Before/After Your Search Term**

Before | After |
---|---|

N/T | NA4NT |

n-tier | NaaS |

n-tier architecture | NAC |

n-type | NACCB |

n-type silicon | Nacchio's law |

N-way | NACK |

n00b | NACOMEX |

N2M | Nacona |

N3 | NADN |

N900 | NAEC |

**Terms By Topic**

Click any of the following categories for a list of fundamental terms.