1. A primitive word, from which spring other words; a radical; a root; an etymon.
  2. 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.
  3. A finite expression, from which a series is derived.
  4. The root of a plant.