Can you become addicted to alcohol?

My father seems to be drinking more frequently than we would consider a normal amount in our house. His behavior does not seem to be impacted in a negative way when he drinks and for the most part everything goes on as normal even when he is drinking to excess. I was speaking with my mother about it the other night and she was expressing some concern that he may be an alcoholic or at the very least have a problem with addiction. My question is fairly simply I am wanting to know if alcohol is addictive? I understand that alcoholism is a think but is that the same thing as being an addict? I hope this makes sense and I am not over explaining the question. Anyways, Thanks in advance!