Gadget

1. A new, often expensive, and relatively unknown hardware device or accessory that makes your life easier and/or more enjoyable or the use of another device easier and/or enjoyable.
   
   As a gadget becomes more well known and widely used in the general public it is no longer referred to as a gadget. For example, when cell phones were first introduced they were considered a gadget. However, as they became more widely used they no longer became gadgets.
   
    
2. When referring to software, a gadget is another name for a widget.

Also see: Accessory, Add-on, Device, Widget