Definition - What does Bowl mean?
A bowl is a part of a marijuana pipe that holds the packed marijuana in place to be smoked. It normally has a little hole (also known as a 'carb' that allows the chamber to be cleared) on its side. The carb needs to be covered while a person is inhaling the cannabis smoke from the opposite end of the pipe.
Physically, a basic cannabis pipe is not so different from a tobacco pipe, but it is generally made up of glass. The bowl pieces are commonly made from meerschaum, clay, briar wood, or even corncob.
Hydrolife explains Bowl
Placing the marijuana on a bowl may not be as easy as it seems. Most of the times, the weed falls through the bowl into the bottom of the glass pipe. In order to ensure that it doesn’t, the weed should not be ground down too finely (such as in a powder) to smoke a bowl. It just has to be ground down small enough to cover a certain surface area and can be pushed down into place with the thumb.
Another way to ensure that the ganja does not fall through the bowl is to use a small chunk of weed (non-ground weed) as a screen. The small chunk can be put in just enough to cover the bowl’s bottom hole, and then topped up with the rest of the ground weed.
The cannabis plant’s stem could also be used as a screen. A stem in the shape of “y” placed upright in the bowl could sufficiently block the ground weed, placed on top of it, from falling through, without blocking the air flow.