A cache is the memory holding area of recently accessed data. Windows has an Internet cache that saves data (e.g., images, scripts) from web sites recently visited, it then stores them on the computers hard drive. This means that next time you visit a stored web site it will load up quicker. This is because it wont have to upload the images and scripts from the web again. However after a certain amount of time this cached data will be overwritten by new data.