whether or not a drug is legal has nothing to do with its status as a drug. don't be fooled by that "drugs and alcohol" bullshit because alcohol is as much as a drug as heroin is.

Main Entry: drug
Function: noun
Etymology: Middle English drogge

A substance other than food intended to affect the structure or function of the central nervous system.

yes, marijuana is a drug. so is alcohol. so is tobbaco.