Drug: something and often an illegal substance that causes addiction, habituation, or
a marked change in consciousness
Drug - Definition and More from the Free Merriam-Webster Dictionary
Clearly, alcohol causes a marked change in consciousness, thus making it a drug according to the Merriam Webster dictionary. But hell, alcohol is a blast when it's used in moderation, and better yet it's a legal drug for those over the age of 21. So let's all stop fighting and get wasted!