What is trespass to chattels?

Answer 1

Either exercising dominion and control over something that belongs to someone else, or doing something that reduces its value, like damaging the item. It's the civil equivalent of the criminal charge of theft, destruction of property, or vandalism. The usual penalty is the reduction in value to the item if damaged, or the costs incurred by the victim as a result of the deprivation.

Answer 2

Chattels is personal property-- so to trespass upon it would be to for someone to unlawfully interfere/infringe on another's lawful use of the chattels.