The most common use of Mockups in software development is to create user interfaces that shows the end user what the software will look like without having to build the software or the underlying functionality.
Mockups
The most common use of Mockups in software development is to create user interfaces that shows the end user what the software will look like without having to build the software or the underlying functionality. Software UI mockups can range from very simple hand drawn screen layouts, through realistic bitmaps, to semi functional user interfaces developed in a software development tool.
Mockups are often used to create Unit tests - there they are usually called Mock objects. The main reasons to create such mockups is to be able to test one part of a software system (a unit) without having to use dependent modules. The function of these dependencies is then "faked" using mock objects.
Mockup Software can also be used for micro level evaluation, for example to check a single function, and derive results from the tests to enhance the products power and usability on the whole.
Mockup Software
Stack Exchange
The User Experience Stack Exchange Network supports balsamiq Mockups for describing an UI in a question.