Source : Webster's Revised Unabridged Dictionary (1913)

Trigonometry \Trig`o*nom"e*try\, n.; pl. {-tries}. [Gr. ? a
   triangle + -metry: cf. F. trigonom['e]trie. See {Trigon}.]
   1. That branch of mathematics which treats of the relations
      of the sides and angles of triangles, which the methods of
      deducing from certain given parts other required parts,
      and also of the general relations which exist between the
      trigonometrical functions of arcs or angles.

   2. A treatise in this science.

   {Analytical trigonometry}, that branch of trigonometry which
      treats of the relations and properties of the
      trigonometrical functions.

   {Plane trigonometry}, and {Spherical trigonometry}, those
      branches of trigonometry in which its principles are
      applied to plane triangles and spherical triangles
      respectively.

Mathematics \Math`e*mat"ics\, n. [F. math['e]matiques, pl., L.
   mathematica, sing., Gr. ? (sc. ?) science. See {Mathematic},
   and {-ics}.]
   That science, or class of sciences, which treats of the exact
   relations existing between quantities or magnitudes, and of
   the methods by which, in accordance with these relations,
   quantities sought are deducible from other quantities known
   or supposed; the science of spatial and quantitative
   relations.

   Note: Mathematics embraces three departments, namely: 1.
         {Arithmetic}. 2. {Geometry}, including {Trigonometry}
         and {Conic Sections}. 3. {Analysis}, in which letters
         are used, including {Algebra}, {Analytical Geometry},
         and {Calculus}. Each of these divisions is divided into
         pure or abstract, which considers magnitude or quantity
         abstractly, without relation to matter; and mixed or
         applied, which treats of magnitude as subsisting in
         material bodies, and is consequently interwoven with
         physical considerations.

Source : WordNet®

trigonometry
     n : the mathematics of triangles and trigonometric functions
         [syn: {trig}]