What is the meaning of -ato?

See -at-

forms nouns from nouns, denoting a status, jurisdiction or period of office; -ate, -dom, -cy, -ship

used with a stem to form the past participle of regular -are verbs

forms adjectives having or resembling the specified thing

a derivative of a specified element or compound; especially a salt or ester of an acid whose name ends in -ico; -ate

-ate (abstract noun), -hood, -ship, -y, -cy

forms the noun denoting the result, product, object, or effect of the action expressed by a verb

second/third-person singular future active imperative of -ō

dative/ablative masculine/neuter singular of -ātus

-ate (derivative of a salt or ester of an acid whose name ends in -ico)

-ate (abstract noun), -ship, -cy, -age

diminutive suffix

-ate (derivative of a salt or ester of an acid whose name ends in -ico)

-ate (abstract noun), -ship, -cy, -age

denotes the office of a noun stem

denotes the action from a noun stem

forms an institution from a noun stem

forms diminutives

Forms nouns from adverbs, adverbial verb forms, and postpositions, typically with the sense of ‘one that (is) …’, ‘one that has the quality of …’.

Forms the plural of the recent past imperfective tense when the arguments of the verb are first- or second-person.

Source: wiktionary.org