What is Assault And Battery?

Legal Definition
Although colloquially used interchangeably, in many jurisdictions, assault and battery are distinct crimes. In such jurisdictions, assault (also called attempted battery) is a threat or physical act that creates a reasonable apprehension of imminent harmful or offensive contact, whereas battery is a physical act that results in that harmful or offensive contact. Assault is a lesser included offence of battery, meaning that assault merges into battery and that a defendant may be punished for one but not both crimes.
Illustrative case law
See, e.g. Claggett v. State, 670 A.2d 1002 (Md. Ct. Spec. App. 1996).
See also
Legal Definition
the legal expression that is sussed to describe the attack of one person against another that results in some sort of bodily injury.