The use of the term "acquisition" has been interpreted so as to require that the Commonwealth (or some other party for a Commonwealth purpose) actually acquire possessory or proprietary rights over the property in question, or at least some benefit: the mere extinguishment of a person's proprietary rights by the Commonwealth (or a prohibition on effectively exercising them) is insufficient to amount to an acquisition. And "just terms" has been taken to mean something less than "just compensation"; in particular, it does not necessarily require payment to the owner of the value of the property when it was compulsorily acquired