Source : Webster's Revised Unabridged Dictionary (1913)

Dependent \De*pend"ent\, a. [L. dependens, -entis, p. pr.
   dependere. See {Depend}, and cf. {Dependant}.]
   1. Hanging down; as, a dependent bough or leaf.

   2. Relying on, or subject to, something else for support; not
      able to exist, or sustain itself, or to perform anything,
      without the will, power, or aid of something else; not
      self-sustaining; contingent or conditioned; subordinate;
      -- often with on or upon; as, dependent on God; dependent
      upon friends.

            England, long dependent and degraded, was again a
            power of the first rank.              --Macaulay.

   {Dependent covenant} or {contract} (Law), one not binding
      until some connecting stipulation is performed.

   {Dependent variable} (Math.), a varying quantity whose
      changes are arbitrary, but are regarded as produced by
      changes in another variable, which is called the
      independent variable.

Source : WordNet®

dependent variable
     n : (statistics) a variable in a logical or mathematical
         expression whose value depends in the independent
         variable; if f(x)=y, y is the dependent variable