Source : Webster's Revised Unabridged Dictionary (1913)

Interchangeable \In`ter*change"a*ble\, a. [Cf. OF.
   entrechangeable.]
   1. Admitting of exchange or mutual substitution.
      ``Interchangeable warrants.'' --Bacon.

   2. Following each other in alternate succession; as, the four
      interchangeable seasons. --Holder. --
      {In`ter*change"a*ble*ness}, n. -- {In`ter*change"a*bly},
      adv.

Source : WordNet®

interchangeable
     adj 1: of or relating to or suggestive of complementation;
            "interchangeable electric outlets" [syn: {complementary},
             {reciprocal}]
     2: (mathematics, logic) such that the arguments or roles can be
        interchanged; "the arguments of the symmetric relation,
        `is a sister of,' are interchangeable"
     3: capable of replacing or changing places with something else;
        "interchangeable parts" [syn: {exchangeable}, {similar}, {standardized},
         {standardised}]