widget
     n : a device that is very useful for a particular job [syn: {appliance},
          {contraption}, {contrivance}, {convenience}, {gadget}, {gizmo},
          {gismo}]
Source: WordNet® 2.0

widget n. 1. A meta-thing. Used to stand for a real object in didactic
   examples (especially database tutorials). Legend has it that the
   original widgets were holders for buggy whips. "But suppose the parts
   list for a widget has 52 entries...." 2. [poss. evoking `window gadget']
   A user interface object in {X} graphical user interfaces.


Source: The Jargon File