The format of the name had many camel case variants, and became NEXTSTEP (all capitals) only at the end of its life. The format most commonly used by "insiders" is NeXTSTEP.
The system had originally started in the mid-1980s as two projects, an effort that would create Display PostScript, and an effort to build a "toolkit" of programming objects for the education market. When it became clear that the computers and operating systems of the day were not up to the task of running either, the projects were combined, along with a hardware effort, and eventually created the NeXT computers.
NeXTSTEP was a combination of several parts:
NeXTSTEP's user interface was refined and consistent, and introduced the idea of the Dock, carried through OPENSTEP and into Mac OS X, and the Shelf. The user interface features did not stop here, but were touches on a smaller level, such as window modification notices (such as the saved status of a file) were inbuilt into all windows, modified scrollbars, and so on.
Additional kits were added to the product line to make the system more attractive. This included Portable Distributed Objects (PDO), which allowed easy remote invocation, and Enterprise Objects Framework, a powerful object-relational database system. These kits made the system particularly interesting to custom application programmers, and NeXTSTEP had a long history in the financial programming community.
After the completion of Apple Computer's acquisition of NeXT in early 1997, Apple decided to make its own implementation of the OpenStep standard, which resulted in Mac OS X. Mac OS X's OpenStep heritage can be seen in the Cocoa development environment, where the Objective-C library objects have "NS" prefixes. A free software implementation of the OpenStep standard, GNUstep, also exists.