A title bar is a section at the top of a window that contains the name or description of the window. Nearly all windows displayed on your computer have a title bar. Therefore, if several windows are tiled across the screen at one time, a user can identify each window by just glancing at the title bar. Windows makes this even easier by placing the information from each window's title bar in the Task Bar. Mac OS X displays the title bar information in the middle of each window when the Exposé function is active.
The title bar is a standard user interface GUI convention used by many applications, as well as the operating system itself. For example, in a Web browser window, the title bar typically is the title of the current Web page. In a word processor window, the title bar is usually the name of the document itself. If the document has not been named or saved yet, the title bar may read "Document 1" or "Untitled." When folders are opened on the Desktop, the folder window typically displays the name of the active folder in the title bar. In Windows, the title bar can also be set to display the full path to the folder's location by selecting "Folder Options" in the Tools menu.
While the title bar serves as an identifier for each window, it also has another important function. By clicking and dragging the title bar, you can move a window to another location on the screen. This is important to know since the title bar is often the only place you can click to move the window. Also, double-clicking the title bar will minimize the window, placing the window in the Task Bar (Windows) or the Dock (Mac OS X).