You didn’t really think that an inventor would provide any form of “normal” dictionary, did you? This page defines some terms of art together with commentary.
IPR (Inter Parties Review): A system set up by the America Invents Act that was intended to provide a cheap and quick way to challenge patent validity. Former Chief Judge Rader of the Federal Circuit (the court charged with hearing all US patent appeals) famously called them “patent death squads” because of the enormous “kill rate” for patents.
Patent Wall (sometimes Patent Thicket): The practical application of the theory is that a single patent is relatively easy to destroy. If you have dozens or hundreds of patents (or many more — for example, smart phones are normally covered by thousands of patents), it becomes a Sisyphean task to destroy every patent. The creation of a patent wall is one of the few viable ways for startups to protect their IP against better funded tech giants (and even then litigation funding is likely required).