The past participles of the three conjugations of regular verbs end in —ato (parlato), —uto (venduto), and —ito (sentito), respectively.
The past participle of avere is regular: avuto
The past participle of essere is irregular: stato.
The past participle of an Italian verb has literally the same meaning as the English past participle equivalent. Thus, parlato means “spoken”; finito, “finished,” etc.
In Italian as in English, the past participle has two uses: as an adjective (in which case it agrees with the noun or pronoun it modifies: una donna preoccupata – a worried woman) and as a part of the verb, to make the perfect (compound) tenses.