Cauldron and Firkin

Cauldron noun - A very large pot that is used for boiling.

Firkin and cauldron are semantically related in holder for physical object topic. In some cases you can use "Firkin" instead a noun "Cauldron".

Firkin noun - An enclosed wooden vessel for holding beverages.

Cauldron and firkin are semantically related in container topic. Sometimes you can use "Cauldron" instead a noun "Firkin", if it concerns topics such as holder for physical object.