An html tag you can stuff in the head of your document. It tells the browser to do various active things when using http. One useful directive is to refresh after a given number of seconds, making the browser request again the same file, or another one named in the tag. A Good Thing to do with this is display a message for a while, or show some (quick loading) status or image which updates every few seconds or minutes. A Bad Thing is to use this for redirecting to a moved page (for instance, search engine crawlers won't understand that). An HTML atrocity to do with this is to make a movie by linking many images, each one to the next, with a short refresh time; if you didn't think anyone would try that, check out the Netscape Fishcam. See also META.