An explorer frame, also known as a browser frame or navigation bar, is a graphical user interface (GUI) element that allows the user to navigate through different sections of a website or application. There are a few different synonyms for this term, depending on the context in which it's used. For example, in web development, an explorer frame is often referred to as a site map or site navigation. In some programming languages, such as Java, it's called a "JFrame" or "window frame." Other possible synonyms might include menu bar, toolbar, or task pane, depending on the specific design and functionality of the interface.