What is the meaning of -arium?

A place associated with a specified thing.

A device associated with a specified function.

-arium

Used primarily to form nouns of purpose from other nouns, such as places where things are kept or objects used for a particular end. See usage notes.

genitive feminine/masculine/neuter plural of -āris

nominative/accusative/vocative neuter plural of -ārius

-arium

Source: wiktionary.org