'Cookies' are small text files that are stored by the browser (for example, Internet Explorer or Safari) on your computer or mobile phone. They allow websites to store things like user preferences. You can think of cookies as providing a 'memory' for the website, so that it can recognise you when you come back and respond appropriately.
A visit to a page on this website may generate only first-party cookies - small amounts of text stored in the user's computer. By default, first-party cookies are allowed in every Web browser. If you were to disable first-party cookies, a Web site could not keep track of your activity as you move from page to page.
It is usually possible to stop your browser accepting cookies, or to stop it accepting cookies from a particular website.
All modern browsers allow you to change your cookie settings. You can usually find these settings in the 'options' or 'preferences' menu of your browser.