A title bar is a graphical user interface (GUI) component of a software application or Web page. It holds related metadata and is used to define the name of a window, software or visible interface.
A title bar is also known as a titlebar.
Techopedia explains Title Bar
A common operating system (OS) and software feature, a title bar provides an opened window's title and associated data. In most instances, a title bar is present at the top of a window and displayed by a horizontal bar. The right corner of a title bar provides options for minimizing, maximizing or closing a window.
By default, a title bar contains opened window names. In some cases, a title bar may be used to display data, such as a primary website or software name, keywords, tags and logos.