From the Free Dictionary — used with permission
For Addiction, see the article here.
Alcoholism is a term with multiple and sometimes conflicting definitions. In common and historic usage, alcoholism refers to any condition that results in the continued consumption of alcoholic beverages despite the health problems and negative social consequences it causes. Medical definitions describe alcoholism as a disease which results in a persistent use of alcohol despite negative consequences. Alcoholism may also refer to a preoccupation with or compulsion toward the consumption of alcohol and/or an impaired ability to recognize the negative effects of excessive alcohol consumption. Although not all of these definitions specify current and on-going use of alcohol as a qualifier, some do, as well as remarking on the long-term effects of consistent, heavy alcohol use, including dependence and symptoms of withdrawal.
While the ingestion of alcohol is, by definition, necessary to develop alcoholism, the use of alcohol does not predict the development of alcoholism. The quantity, frequency and regularity of alcohol consumption required to develop alcoholism varies greatly from person to person. In addition, although the biological mechanisms underpinning alcoholism are uncertain, some risk factors, including social environment, emotional health and genetic predisposition, have been identified.
Definitions and Terminology
The definitions of alcoholism and related terminology vary significantly between the medical community, treatment programs, and the general public.
The Journal of the American Medical Association defines alcoholism as “a primary, chronic disease characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking.” 
The DSM-IV (the standard for diagnosis in psychiatry and psychology) defines alcohol abuse as repeated use despite recurrent adverse consequences. ; further defining alcohol dependence as alcohol abuse combined with tolerance, withdrawal, and an uncontrollable drive to drink. (See DSM diagnosis below.)
According to the APA Dictionary of Psychology, alcoholism is the popular term for alcohol dependence. Note that there is debate whether dependence in this use is physical (characterised by withdrawal), psychological (based on reinforcement), or both.
Many terms are applied to a drinker’s relationship with alcohol. Use, misuse, heavy use, abuse, addiction, and dependence are all common labels used to describe drinking habits, but the actual meaning of these words can vary greatly depending upon the context in which they are used. Even within the medical field, the definition can vary between areas of specialization. The introduction of politics and religion further muddles the issue.
Use refers to simple use of a substance. An individual who drinks any alcoholic beverage is using alcohol. Misuse, problem use, and heavy use do not have standard definitions, but suggest consumption of alcohol beyond the point where it causes physical, social, or moral harm to the drinker. The definitions of social and moral harm are highly subjective and therefore differ from individual to individual.
Within politics, abuse is often used to refer to the illegal use of any substance. Within the broad field of medicine, abuse sometimes refers to use of prescription medications in excess of the prescribed dosage, sometimes refers to use of a prescription drug without a prescription, and sometimes refers to use that results in long-term health problems. Within religion, abuse can refer to any use of a poorly regarded substance. The term is often avoided because it can cause confusion with audiences that do not necessarily share a single definition.
Remission is often used to refer to a state where an alcoholic is no longer showing symptoms of alcoholism. The American Psychiatric Association considers remission to be a condition where the physical and mental symptoms of alcoholism are no longer evident, regardless of whether or not the person is still drinking. They further subdivide those in remission into early or sustained, and partial or full. Others (most notably Alcoholics Anonymous) use the term recovery to describe those who have completely stopped consumption of alcohol, and have begun a process of addressing the underlying emotional and social predisposing factors.