CACHING is a technique for saving numerous COPIES of the most frequently used data in a temporary storage area (or cache) so that they can be accessed more quickly. It keeps data in a temporary format for software applications, servers, and web browsers, so users don't have to download information every TIME they VISIT a website or use an application.

Cached data works by saving data in a device's memory for later access. The data is kept in the memory of a computer, directly below the central processing unit (CPU). The primary cache level is incorporated into a device's microprocessor CHIP, followed by two more secondary cache levels that feed the primary level. This information is kept until the content's time to live (TTL), which specifies how long it should be cached, expires or the device's disc or hard drive cache fills up.

Data is usually cached in one of two ways: browser or memory caching (data stored locally on the computer) or Content Delivery Networks (data stored in geographically distributed locations).