Source : Webster's Revised Unabridged Dictionary (1913)

Radix \Ra"dix\, n.; pl. {Radices}, E. {Radixes}. [L. radix,
   -icis, root. See {Radish}.]
   1. (Philol.) A primitive, from which spring other words; a
      radical; a root; an etymon.

   2. (Math.)
      (a) A number or quantity which is arbitrarily made the
          fundamental number of any system; a base. Thus, 10 is
          the radix, or base, of the common system of
          logarithms, and also of the decimal system of
          numeration.
      (b) (Alg.) A finite expression, from which a series is
          derived. [R.] --Hutton.

   3. (Bot.) The root of a plant.