Burglary is generally the unlawful entry of a building or structure to commit a felony criminal offense (crime), theft, or assault. The definition of burglary varies from state to state (and in the federal system), and some states have different degrees of severity of the burglary offense, depending on the nature of the unlawful entry (type of building or structure), the intended purpose, and the illegal action taken by the defendant once inside the building or structure. In some states, breaking into an automobile, a coin-operated machine, or an ATM (automated teller machine) with the intent to commit a theft may also constitute the crime of burglary.

A defendant generally commits the offense of burglary of a building or habitation (1) by entering a private habitation or any part of a building that was not open to the public, (2) without the consent of the owner, and (3) with the intent to commit a felony, theft, or assault.

A defendant may also commit the offense of burglary of a building or habitation by entering with consent, but remaining hidden with the intent to commit a felony, theft, or assault—or entering with consent and attempting to commit a felony, theft, or assault, or actually committing a felony, theft, or assault.

Some states make a distinction between burglary of a habitation (a place used for overnight accommodations) and burglary of a building that is not a habitation (home). Burglary of a habitation is usually treated as a more serious offense with greater penalties.

In New Jersey, burglary is defined under N.J.S.A. 2C:18-2 as entering or surreptitiously remaining in a research facility, structure, or separately secured or occupied portion thereof, when not licensed or privileged to do so, with the purpose to commit an offense therein. The offense is typically considered a crime of the second degree if the burglar purposely, knowingly, or recklessly inflicts, attempts to inflict, or threatens to inflict bodily injury on anyone, or if armed with or displays what appear to be explosives or a deadly weapon. Otherwise, burglary is considered a crime of the third degree in New Jersey. The state distinguishes between burglary of a dwelling, which is treated more seriously, and burglary of other structures. The intent to commit a crime is a critical element of burglary, and the intended crime does not need to be theft; it can be any felony or certain misdemeanors. New Jersey law does not specifically categorize burglary by degrees of severity based on the type of structure entered, but the penalties may vary depending on the circumstances of the offense and the presence of aggravating factors.