Definitions:
a container or device in which water is boiled, having a lid, spout, and handle.

a depression in the ground thought to have been formed by the melting of an ice block trapped in glacial deposits, especially one that is circular and deep

a small area in which demonstrators or protesters are confined by police seeking to maintain order during a demonstration

(of the police) confine (a group of demonstrators or protesters) to a small area, as a method of crowd control during a demonstration