A multistage (or multi-stage) rocket's a rocket that uses two or more stages, each of which contains its own engines and propellant. A tandem or serial stage's mounted on top of another stage; a parallel stage's attached alongside another stage. The result's effectively two or more rockets stacked on top of or attached next to each other. Taken together these are sometimes called a launch vehicle. Two stage rockets are quite common, but rockets with as many as five separate stages have been s… (More on Two-stage)