Well, possession of drugs means just that. That you are in actual possession of the drugs that you're being charged with. You could also be charged with constructive possession, means drugs that you are near or have access to. Dealing on the other hand means that you have either sold drugs, usually to an undercover officer, or maybe have received drugs as part of a sale. Trafficking drugs usually involves the amount of drugs in the offense, usually high amounts of drugs, sometimes many ounces, many pounds, depending on the type of drug. Every drug has different levels when it comes to whether or not you'd be charged with trafficking. Trafficking also has minimum mandatory offenses. There's three year, seven year, and fifteen year minimum mandatory offenses for trafficking charges, depending on the amount of drugs involved.