Assault is the crime of using violence against another person. In some jurisdictions (e.g. England or Australia), assault is used to refer to the actual violence, while in other jurisdictions (e.g. some in the United States), assault refers only to the threat of violence, while the actual violence is called battery.
Assault is often defined to include not only violence, but any physical contact with another person without their consent. When assault is defined like this, exceptions are provided to cover such things as normal social intercourse (for example, patting someone on the back).
In some jurisdictions, consent is a defence to assault, while in other jurisdictions (most notably England) it is not. This can have important consequences when dealing with issues such as sadomasochistic sexual activity. In England, several men have been successfully convicted of assault for engaging in sadomasochistic activities, even though the activity was consensual.