(operating systems) (LRU) A rule USed in a paging system which selects a page to be paged out if it has been USed (read or written) less recently than any other page. The same rule may also be USed in a cache to select which cache entry to flUSh. This rule is based on temporal locality - the observation that, in general, the page (or cache entry) which has not been accessed for longest is least likely to be accessed in the near future. (1995-02-15)