This is equivalent to the English present participle — i.e. the part of the verb ending in -ing, like thinking, running, talking, going etc.
The Adverbial Present Participle or gerund ("gerundio") is formed by adding a suffix to the verb stem:
Adverbial participles answer questions about the action expressed by the main verb. Examples:
They are used like English present participles to form progressive tenses with the verb "stare":
Because they function as adverbs, defining an action, these participles are invariable in form, and do not agree in gender or number with the subject of the verb.
The Adverbial Present Participle (Gerundio perfetto) is formed with the adverbial present participle of the auxiliary verb and the past participle of the main verb: "avendo parlato" (having spoken); "essendo arrivato" (having arrived).
The Italian name "gerundio" has led to the use of the English word "gerund" to denote adverbial participles. This is misleading, since the English gerund is a verbal noun ("Walking is good exercise"). It is best for English--speaking students to avoid using the term "gerund" when studying the Romance languages like Spanish and Italian. Examples:
The ending follows the form of unisex adjectives ending in "_e," changing to "_i" in the plural: "l'uomo dormente" (the sleeping man); "le lezione seguenti" (the following lessons).