A battery is committed when a person willfully and unlawfully touched the victim in a harmful or offensive manner and the person did not act in self-defense or in defense of someone else or while reasonably disciplining a child.
The slightest touching can be enough to commit a battery if it is done in a rude or angry way.   The touching does not have to cause pain or injury of any kind.
The touching can be done indirectly by causing an object or someone else to touch the other person.
A battery is a misdemeanor.