(1) A folder full of Web pages in the user's computer that is maintained by the Web browser for a period of time. If the local, cached page has not been updated on the Web, it is retrieved immediately by the browser, saving download time.|
(2) A computer system in a network that keeps copies of the most-recently requested Web pages in memory or on disk in order to speed up retrieval. If the next page requested has already been stored in the cache, it is retrieved locally rather than from the Internet. Web caching servers (or caching servers or cache servers) sit inside the company's firewall and enable all popular pages retrieved by users to be instantly available. Since the content of Web pages can change, the caching software is always checking for newer versions of the page and downloading them. Pages will be deleted from the cache after a set amount of non-activity. See browser cache, proxy cache, transparent cache. See also Akamai.
Holding up to 2TB of Web pages, this NetCache model is called a "caching appliance," because it plugs into the network and does only Web caching. (Image courtesy of Network Appliance, Inc.)