Certainly there is more than one word for things, which is why I said normally.  We used to call it dope in high school because that is what the police called it when they toured around to our school telling us not to do drugs.  The police used that word for a reason because it has such a negative connotation.  You're smoking dope because you look like a dope and you are a dope.  When I got out of high school and met people who knew their drugs I realized that to those who use, dope means heroin.

I would not advise asking for dope when you want weed.  You will look like a narc, or you will get heroin (neither of which is a good thing).