swap

swap (http://definr.com/swap)

     n : an equal exchange; "we had no money so we hd to live by
         barter" [syn: barter, swop, trade, quid pro quo]
     v 1: exchange or give (something) in exchange for [syn: trade,
          swop, switch]
     2: move (a piece of a program) into memory, in computer science