ProfessorBoehm introduced the term "WaterFall", and the whole concept of phases. 

He produced the idea after comparing software "authoring" with more traditional engineering practices, most of which use the WaterfallModel. Less than six months later, he actually retracted the idea saying that his article was trying to introduce the idea of a life-cycle, not any particular model. By that time it was too late. 

Also see BarryBoehm.