fungible

paljousesine

korvattava puhekieltä Able to be substituted for something of equal value or utility; interchangeable, exchangeable, replaceable.
1876 1877, w:Samuel Dana Horton|Samuel Dana Horton, Silver and Gold and Their Relation to the Problem of Resumption, http://books.google.ca/books?id=MaRvQUCsod8C&dq=fungible&pg=PA116 page 116:

Gold is fungible. Silver is fungible; that is, these metals are both so homogeneous that, if I get a pound of pure gold, for example, it is indifferent to me whether it be this pound or that pound, one is as good as another

At the core of Kasarda’s conception of the aerotropolis lies the notion that space – unlike time – is fungible.