A bong is a type of water pipe used for smoking.
When people talk about bongs, they're usually referring to the device itself, which looks like a big glass tube with water inside. You put marijuana or tobacco into it and inhale through the mouthpiece at the top. Some people use bongs because they think the smoke is easier on the lungs than smoking directly from a joint or cigarette. Others just prefer the way the smoke tastes when it's filtered through the water. Bongs can be pretty fancy, with all sorts of decorations and shapes, but the basic idea is always the same – to make smoking more relaxed and maybe even a little cooler-sounding.
(slang) The clang of a large bell.
Example: The sound of a bong echoed across the courtyard, signaling the hour.
