The Restatement states:
An actor is subject to liability to another for battery if
(a) he acts intending to cause a harmful or offensive contact with the person of the other or a third person, or an imminent apprehension of such a contact, and
(b) a harmful contact with the person of the other directly or indirectly results.
Another way to think about battery is that there are three elements:
- An intent to commit a harmful touching,
- that results in harmful or offensive contact,
- and causation between the first two elements.
While assault and battery are often paired in peoples' minds, there is a difference: battery requires actual contact, while assault can be brought simply for causing the apprehension of contact.
It is said that "personal indignity is the essence of an action for battery. Therefore, a charge of battery can be brought for contact with any thing that can be "practically identified" with the body, such as clothing or something held in the hand. Furthermore, there is no requirement that a victim be aware of the contact - the victim can be asleep or unconscious.
For battery, the act must cause and be intended to cause the offensive contact. But, physical harm is not necessary, so spitting in someone's face or knocking an item from someone's hand can support battery. Furthermore, a joke, such as an un-consented to kiss, can qualify as battery, since it is the offensive and harmful consequences that support the charge. But, day-to-day contact carries the assumption of consent: hence, a tap on the shoulder or incidental jostling on the street will likely not support a charge of battery.