trifling |
of little importance, meaning, or value; slight; trivial. [2 definitions] |

trifocal |
of eyeglasses, having three lenses of different focal lengths. [2 definitions] |

trifoliate |
having three leaves, leaflets, lobes, or the like. [2 definitions] |

trifoliolate |
having three leaflets, or having leaves that have three leaflets, as clover. |

trig |
(informal) trigonometry. |

trigeminal |
of or pertaining to the trigeminal nerve. |

trigeminal nerve |
either one of the fifth pair of cranial nerves that conduct impulses from the head and face to the brain. |

trigger |
a small lever that when pressed or pulled causes a firearm to fire, or a similar lever on another device or machine. [4 definitions] |

trigger finger |
the finger used to pull the trigger of a gun, usu. the index finger. |

trigger-happy |
(informal) ready to use force, esp. by firing a gun, at the slightest provocation, regardless of consequences. [2 definitions] |

triglyceride |
an ester derived from glycerol and three fatty acid radicals which is the main component of fats and oils. |

trigonometric function |
a function, such as sine, cosine, or tangent, expressed as the ratio of different sides of a right triangle. |

trigonometry |
the branch of mathematics concerned with the relationships between sides and angles of right triangles, and with calculations based on these relationships. |

trihedral |
having three planes that meet in a point. [2 definitions] |

trihedron |
a figure formed by three planes that meet in a point; trihedral. |

trike |
(informal) a tricycle. |

trilateral |
three-sided. |

trilingual |
using or speaking three languages, esp. with equal skill in all three. [2 definitions] |

trill |
a rapid tremulous alternation of one musical tone with an adjacent whole or half tone; vibrato; tremolo. [5 definitions] |

trillion |
the number represented by the Arabic numeral 1,000,000,000,000. [5 definitions] |

trillium |
a perennial of the lily family that has a whorl of three leaves from which a single three-petaled flower blooms. |