Tabs may appear in a horizontal bar or as a vertical list, of which the former takes typically less screen space whereas the latter can show more items at once while still having space for individual titles.
GUI tabs are modeled after traditional card tabs inserted in paper files or card indexes (in keeping with the desktop metaphor). It is an interface style most commonly associated with web browsers, web applications, text editors, and preference panes, with window managers, especially tiling window managers, being lesser known examples. In interface design, a tabbed document interface ( TDI) or Tab is a graphical control element that allows multiple documents or panels to be contained within a single window, using tabs as a navigational widget for switching between sets of documents. Vertical tabs, to the left, represent languages in which a given spelling occurs, where the selected tab shows the word jam ('already') in Esperanto.
Example of tabbed interface with two sets of tabs: Horizontal tabs, at the top, allow navigation to different pages within the Wiktionary website.
