The term "Whiteacre" is a fictional plot or a piece of land, which is often used by legal professors or scholars to discuss and explain real property cases or law.
For explanation and demonstration purposes, there are many fictitious placeholder names used: Whiteacre, Blackacre, Greenacre, etc.
In common law jurisdiction, professors of law often use these fictitious names representing fictitious estates. These scenarios are mostly from real estate and involve the discussion of the rights of different parties on a piece of real property.