The symbol of two vertical lines descending from a circle and encompassing a rectange indicates a condition of ownership:

As we shall soon see, the condition of ownership exists in the answer to these fundamental questions:

•  Is the object available to be owned (i.e. is not something which cannot be owned, such as another owner, or an object or property already owned by another owner)?
  
• May I, without asking anyone's permission or consulting with anyone else, rightfully do as I please with the object (property) without sharing with anyone else either the object or the fruits of production resulting from it, including using it or disposing of it in any way that I please, using it up, selling it, giving it away, keeping it, or even destroying it?

If the answer to both is in the affirmative, then a condition of ownership properly exists.