English Computing Dictionary
Waterfall Model
A {software life-cycle} or {product life-cycle}
model, described by W. W. Royce in 1970, in which development
is supposed to proceed linearly through the phases of
{requirements analysis}, design, implementation, testing
(validation), integration and maintenance. The Waterfall
Model is considered old-fashioned or simplistic by proponents
of {object-oriented design} which often uses the {spiral
model} instead.
Earlier phases are sometimes called "upstream" and later ones
Compare: {iterative model}.
[W. W. Royce, "Managing the Development of Large Software
Systems", Proceedings of IEEE WESCON, August 1970].