Battery is generally a harmful or offensive contact with another person, without the person’s consent. Battery may be the basis for a criminal charge or offense. The definition and penalties for battery vary from state to state, and are usually located in a state's penal or criminal code (statutes). In some states the crimes of assault and battery are merged into one criminal offense.

Battery is also recognized in tort law as an intentional tort, and may result in civil liability (money damages) in a lawsuit against a person who commits battery.

In Illinois, battery is defined under the Illinois Compiled Statutes as causing bodily harm to another person or making physical contact of an insulting or provoking nature with an individual without their consent. The criminal offense of battery is separate from assault in Illinois, with assault being the act of placing another in reasonable apprehension of receiving a battery. Criminal battery is typically classified as a Class A misdemeanor, which can result in fines and imprisonment. However, aggravated battery, which involves more serious circumstances such as the use of a deadly weapon or battery against certain protected classes of people (e.g., children, elderly, pregnant women, law enforcement officers), is a felony with more severe penalties. In addition to criminal charges, a person who commits battery may also face civil liability in a personal injury lawsuit, where the victim can seek monetary damages for injuries suffered due to the intentional act of battery.