Burglary is typically defined as the unlawful entry into almost any structure (not just a home or business) with the intent to commit any crime inside (not just theft/larceny). No physical breaking and entering is required; the offender may simply trespass through an open door. Unlike robbery, which involves use of force or fear to obtain another person's property, there is usually no victim present during a burglary.

For example, Dan enters Victor's boathouse through an open window, intending to steal Victor's boat. Finding the boat is gone, Dan returns home. Though he took nothing, Dan has committed burglary.