Source : Webster's Revised Unabridged Dictionary (1913)

Adherence \Ad*her"ence\, n. [Cf. F. adh['e]rence, LL.
   adhaerentia.]
   1. The quality or state of adhering.

   2. The state of being fixed in attachment; fidelity; steady
      attachment; adhesion; as, adherence to a party or to
      opinions.

   Syn: {Adherence}, {Adhesion}.

   Usage: These words, which were once freely interchanged, are
          now almost entirely separated. Adherence is no longer
          used to denote physical union, but is applied, to
          mental states or habits; as, a strict adherence to
          one's duty; close adherence to the argument, etc.
          Adhesion is now confined chiefly to the physical
          sense, except in the phrase ``To give in one's
          adhesion to a cause or a party.''

Source : WordNet®

adherence
     n 1: faithful support for a religion or cause or political party
          [syn: {attachment}, {adhesion}]
     2: the property of sticking together (as of glue and wood) or
        the joining of surfaces of different composition [syn: {adhesiveness},
         {adhesion}, {bond}]