An owner has a fence that mistakenly extends one foot over the lot line onto a neighbor's property. This is an example of:

This situation is a clear example of encroachment, which occurs when a structure or fixture, such as a fence, intrudes upon a neighbor's property. In this case, the owner's fence extends one foot over the lot line, thereby violating the property boundaries of the adjacent land.

Encroachments can lead to disputes between property owners, as they represent a physical invasion of one property by another. This concept is important in real estate because property owners have the right to use and maintain their property without unnecessary interference from others. Understanding encroachment helps in managing property lines and ensuring that any structures are correctly placed to avoid legal issues with neighbors.

The other terms listed relate to different legal concepts related to property rights. A license refers to permission granted to enter someone's property for a specific purpose. Easement by necessity occurs when a property is landlocked and requires access over another property, while easement by prescription involves the right to use another's property after a certain period of continuous, open, and uninterrupted use. None of these terms correctly apply to the situation described, making encroachment the most appropriate classification.