A rectangular field on screen that accepts typed-in text in order to look up something or launch a search for related information. Also called a "search bar." See search engine
Encyclopedia Search Boxes
These are the search boxes for this encyclopedia on a Web page (top) and in the Windows version (bottom).
The Browser Search Box
Web browsers include search boxes for popular search engines. The box is typically located on the upper right side of the window as in this Firefox browser/Google search example. See address bar