Generic role-playing game system

A generic or universal role-playing game system is a role-playing game system designed to be independent of setting and genre. Its rules should, in theory, work the same way for any setting, world, environment or genre in which one would want to play.
History.
The term "generic" has been used since the earliest days of gaming to describe a system that can be used for any type or style of game. There is some dispute among role-playing enthusiasts on when the concept of a generic system originated and which was the first one published.
According to Shannon Appelcline, Chaosium's "Basic Role-Playing" ("BRP", 1980), was the first generic role-playing system. "BRP" was a "cut-down" version of Chaosium's "RuneQuest" role-playing game and formed the foundation for the "Stormbringer" RPG, and was also adopted for "Call of Cthulhu", the first horror role-playing game. The publication of "GURPS" ("Generic Universal Role-Playing System", 1986) as a completely setting-independent game and its commercial and creative success added credence to the movement. The development of the "Hero System" (1989) from the superhero role-playing game "Champions" also had a profound influence in popularizing the concept.
It truly became a dominant subject in RPG design with the release of the Third Edition of "Dungeons & Dragons" (2000) and the "d20 System" along with the creation of the Open Gaming License (OGL).
Definition.
The "Fuzion" 5.02 rules uses the term "generic" to describe its basic ruleset as separate from its "Champions" and "Interlock" forerunners. 
In the second paragraph of the introduction to "GURPS" 3rd Edition the authors define "generic" as a means to satisfy players and game masters of many styles of play and feel for rules. 
This is repeated in the updated 4th edition rules along with acknowledgments to "Champions" as the first truly flexible character creation system.
Some "d20" derivative, such as Green Ronin Publishing's Mutants & Masterminds and "True20 Adventure Roleplaying", are presented as fully generic systems.