Gerunds and Gerundives

The gerund is a neuter noun meaning the act of X-ing. It is not used in the nominative or in the accusative as a direct object (for these purposes the infinitve is used instead). 

The gerund is often used in the accusative with ad to express PURPOSE, in the genitive after nouns such as ars (art) or followed by the postpostion causa (for the sake of), or instrumentally in the ablative…