The Collaborative International Dictionary of English v.0.48:

Fundamental \Fun`da*men"tal\, a. [Cf. F. fondamental.]
   Pertaining to the foundation or basis; serving for the
   foundation. Hence: Essential, as an element, principle, or
   law; important; original; elementary; as, a fundamental
   truth; a fundamental axiom.
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         The fundamental reasons of this war.     --Shak.
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         Some fundamental antithesis in nature.   --Whewell.
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   Fundamental bass (Mus.), the root note of a chord; a bass
      formed of the roots or fundamental tones of the chords.

   Fundamental chord (Mus.), a chord, the lowest tone of which
      is its root.

   Fundamental colors, red, green, and violet-blue. See
      Primary colors, under Color.
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