What is the meaning of -tus?

alternative form of -us (forms nouns from verbs, describing an action or event)

romanization of -𐍄𐌿𐍃

Forms the past participle of verbs.

Forms adjectives having the sense "provided with".

Forms action nouns from verbs.

Forms collective/abstract nouns from adjectives or other nouns.

-ly; used to form adverbs.

Source: wiktionary.org