[1] : The Collaborative International Dictionary of English v.0.48

addiction \addic"tion\, n. cf. l. addictio an adjudging.
   the state of being addicted; devotion; inclination. "his
   addiction was to courses vain." --shak.
   1913 webster

[2] : WordNet (r) 2.0

addiction
     n 1: being abnormally tolerant to and dependent on something that
          is psychologically or physically habit-forming
          especially alcohol or narcotic drugs syn: dependence,
           dependency, habituation
     2: an abnormally strong craving
     3: roman law a formal award by a court sentence of a thing or
        person to another as of a debtor to his creditor; a
        surrender to a master; "under roman law addiction was the
        justification for slavery"
see also:
dependence dependency habituation 

[3] : Moby Thesaurus II by Grady Ward, 1.0

25 moby thesaurus words for "addiction":
   a habit, acquired tolerance, acute alcoholism, addictedness,
   alcoholism, amphetamine withdrawal symptoms, barbiturate addiction,
   barbiturism, chain smoking, chronic alcoholism, cocainism, crash,
   craving, dependence, dipsomania, drug addiction, drug culture,
   drug dependence, habituation, nicotine addiction,
   physical dependence, psychological dependence, tolerance,
   withdrawal sickness, withdrawal symptoms

Addiction >> A Words
Addiction, definition of term: Addiction
addiction_pag1.html

Drug Addiction >> D Words
Drug Addiction, definition of term: Drug Addiction
drug+addiction_pag1.html