Burglary is when someone enters physical property, not his or her own, without permission, with the intent to commit a crime. The crime could be to take belongings from the property (i.e. theft), or against a person within the property (i.e. assault). This could be a residence (residential burglary), a place of business (commercial burglary), a detached storage shed or garage (also residential), or even a public storage unit or storage yard (also commercial).
It doesn't matter if force is used to gain entry, if someone was home at the time (in the case of a residential burglary) and it doesn't matter is something is stolen. The unlawful entry of the property with intent to commit a crime is burglary.
For the record, most residential burglaries occur during the day, (when people are away at work) and most commercial burglaries occur at night (when the site is more likely to be vacant).