Assault is a
crime of
violence against another
person. In some
jurisdictions, including
Australia and
New Zealand, assault refers to an act that causes another to apprehend immediate and personal violence, while in other jurisdictions, such as the
United States, assault refers only to the threat of violence caused by an immediate show of force.
Simple assaults that do not involve any
aggravation such as use of a deadly
weapon are distinguished from aggravated assaults in some jurisdictions.
Assault is often defined to include not only violence, but any physical contact with another person without their consent.
In common law jurisdictions, including England and Wales and the USA, battery is the crime that represents the unlawful physical contact, though this distinction does not exist in all jurisdictions. Exceptions exist to cover unsolicited physical contact which amount to normal social behavior (for example, patting someone on the back): see (in England and Wales)
Collins v. Wilcox [1984] 3 All ER 374.
http://en.wikipedia.org/wiki/Assault