metal ring; link
General term for a metal ring or link, such as a chain link or a ring-shaped fitting. Often used in technical or craft contexts.
One link of this chain has come off.
kettle ring; tea ceremony ring
Specifically a ring made of twisted metal wire, placed inside a kettle so it can be lifted during the tea ceremony. Highly specialized term.
In the tea ceremony, a kettle ring is placed inside the kettle to lift it.
The kanji 鐶 combines 金 (metal) and 環 (ring), suggesting a metal ring. The reading かん is likely derived from the on'yomi of 環. The exact historical derivation is uncertain.