An assault is the act of inflicting physical harm or unwanted physical contact upon a person or, in some specific legal definitions, a threat or attempt to commit such an action. It is both a crime and a tort and, therefore, may result in either criminal and/or civil liability. Generally, the common law definition is the same in criminal and tort law.
Traditionally, common law legal systems had separate definitions for assault and battery. When this distinction is observed, battery refers to the actual bodily contact, whereas assault refers to a credible threat or attempt to cause battery. Some jurisdictions combined the two offences into assault and battery, which then became widely referred to as "assault". The result is that in many of these jurisdictions, assault has taken on a definition that is more in line with the traditional definition of battery. The legal systems of civil law and Scots law have never distinguished assault from battery.
Assault usually accompanies battery if the assailant both threatens to make unwanted contact and then carries through with this threat. See common assault. The elements of battery are (1) a volitional act (2) done for the purpose of causing a harmful or offensive contact with another person or under circumstances that make such contact substantially certain to occur and (3) which causes such contact. Thus throwing a rock at someone for the purpose of hitting them is a battery if the rock in fact strikes the person, and is an assault if the rock misses.
Aggravated assault is, in some jurisdictions, a stronger form of assault, usually using a deadly weapon. A person has committed an aggravated assault when that person attempts to:
cause serious bodily injury to another person with a deadly weapon
have sexual relations with a person who is under the age of consent
cause bodily harm by recklessly operating a motor vehicle during road rage; often referred to as either vehicular assault or aggravated assault with a motor vehicle.
Aggravated assault can also be charged in cases of attempted harm against police officers or other public servants.