1. In software, a frame is an edge or border that resembles a physical frame you would find around a picture. Frames are often used in word processing, and graphic arts to help focus a viewer's attention.
2. In data or network communications, a frame is a data transmission unit with a header to indicate the beginning of a block of data and a trailer to indicate the end of it.
3. When referring to the Internet, a frame is a movable or non-movable portion of a web page that is either loaded from the a server to help make navigation easier and to bring other content into the page. A good example of this technique in use is with Internet advertising banners.