The decision has this definition in the first paragraph, which I think is reasonably clear: "When a patentee sells one of its products, however, the patentee can no longer control that item through the patent laws—its patent rights are said to 'exhaust.'" (It sounds to me like the plain-English sense of "run out": there are no more patent rights left after the sale, they have been used up in the process of getting the product on the shelves and sold in preference to a competitor's product.)
If I'm reading the decision right, the question is not whether patent rights "exhaust" in the common case when you sell things (everyone agrees that they do). The question is whether Lexmark, by putting conditions on the sale, can prevent their rights from exhausting. The federal circuit's interpretation was, yes, the rights would exhaust, except that when Lexmark put conditions on the sale that the toner-cartridge purchaser agreed to, Lexmark retained its rights because that's a legal and valid contract between the buyer and seller. SCOTUS said, no, it doesn't work that way, the rights were definitely exhausted:
"Lexmark exhausted its patent rights in the Return Program cartridges that it sold in the United States. A patentee’s decision to sell a product exhausts all of its patent rights in that item, regardless of any restrictions the patentee purports to impose. As a result, even if the restrictions in Lexmark’s contracts with its customers were clear and enforceable under contract law, they do not entitle Lexmark to retain patent rights in an item that it has elected to sell."
Wikipedia has some articles about it:
https://en.wikipedia.org/wiki/Exhaustion_of_intellectual_pro...
https://en.wikipedia.org/wiki/Exhaustion_doctrine_under_U.S....
If I'm reading the decision right, the question is not whether patent rights "exhaust" in the common case when you sell things (everyone agrees that they do). The question is whether Lexmark, by putting conditions on the sale, can prevent their rights from exhausting. The federal circuit's interpretation was, yes, the rights would exhaust, except that when Lexmark put conditions on the sale that the toner-cartridge purchaser agreed to, Lexmark retained its rights because that's a legal and valid contract between the buyer and seller. SCOTUS said, no, it doesn't work that way, the rights were definitely exhausted:
"Lexmark exhausted its patent rights in the Return Program cartridges that it sold in the United States. A patentee’s decision to sell a product exhausts all of its patent rights in that item, regardless of any restrictions the patentee purports to impose. As a result, even if the restrictions in Lexmark’s contracts with its customers were clear and enforceable under contract law, they do not entitle Lexmark to retain patent rights in an item that it has elected to sell."