A. Enter. The word “enter,” when constituting an element or part of a crime, includes the entrance of the person, or the insertion of any part of his body, or any instrument or weapon held in his hand and used or intended to be used to threaten or intimidate a person or to detach or remove property.

B. Enters or remains unlawfully. A person “enters or remains unlawfully” in or upon premises when he is not then licensed, invited, or otherwise privileged to so enter or remain. A license or privilege to enter or remain in a building which is only partly open to the public is not a license or privilege to enter or remain in that part of a building which is not open to the public. A person who enters or remains upon unimproved and apparently unused land, which is neither fenced nor otherwise enclosed in a manner designed to exclude intruders, does so with license and privilege unless notice against trespass is personally communicated to him by the owner of the land or some other authorized person, or unless notice is given by posting in a conspicuous manner.

D. “Premises” means and includes any building, dwelling, or any real property.