The law does not need formal definitions like that. Law isn't programming, this is what nerds usually forget.
Legal definitions are usually based on common sense and the "flies like a duck, quacks like a duck, ..." principle.
A clumsy first approximation: If the purpose and intended use of the thing is to provide access to or greatly help in finding access to the infringing content, then it's "linking" to that content.
Legal definitions are usually based on common sense and the "flies like a duck, quacks like a duck, ..." principle.
A clumsy first approximation: If the purpose and intended use of the thing is to provide access to or greatly help in finding access to the infringing content, then it's "linking" to that content.