cache 
Computer caches come in many varieties, but they all work the same way: They store information you use frequently so that you can get it fast. For instance, a Web browser cache takes the pages, graphics, and sounds of the Web sites you visit and stores them on your hard drive; that way, when you revisit a site, your computer doesn't have to download the whole page all over again. Another example: disk caching, in which a program tracks the data your computer reads from disk most often and copies it into RAM, where it can be accessed very quickly.