Definition of "kettling"

A crowd control technique, used by police, where a hostile group of protesters or rioters are surrounded and not allowed to disperse, sometimes with the use of temporary fencing to corral and isolate portions of the group.  examples

The situation where water gets trapped in the heat exchanger of a boiler (e.g. due to limescale build-up), resulting in knocking sounds as it turns into expanding steam.  examples

present participle and gerund of kettle  examples