1. （尤指为建筑物提供集中供暖的）汽锅，锅炉
A boiler is a device which burns gas, oil, electricity, or coal in order to provide hot water, especially for the central heating in a building.

1. sealed vessel where water is converted to steam

Synonym: steam boiler

2. a metal pot for stewing or boiling
usually has a lid

Synonym: kettle