bowl

the part of a marijuana (weed, pot, ganja, etc.) pipe in which the marijuana is placed (packed) to be smoked. it may have a little hole (carb) on the side of it, which you cover while you are inhaling the marijuana smoke while holding the whole pipe and smoking.

bowl (n): the indentation in a pipe (generally a marijuana pipe) in which the marijuana itself is placed

Very simple device, used to hold unstable food.

Bowl is the name for a pipe that weed is smoked out of. While it is technically the term used for the area in which the weed is packed, it is a term experienced potheads use for the whole pipe, because pipes are generally associated with flavored tobacco and grandfathers. If you're trying to impress a pothead with your extensive knowledge of smoking vocabulary, you should therefore use this term, or the widely-used term piece (also associated more with weed than tobacco).

The part of a device for smoking marijuana that hold the weed itself.
The pipe itself is NOT called a bowl. That is a common mistake; stop making it. Call it a pipe or a glass piece, but don't call the whole device a bowl around anyone who knows anything if you don't want to look stupid.

a non mechanical device used to make ones self and others fucked out of their minds

Can also be used to describe .5 grams of marijuana, just enough to fit into the bowl of a pipe.