ALL meanings of sustainer
sus·tain·er
S s - noun sustainer a person or thing that sustains. 1
- noun sustainer Rocketry. any stage of a multistage rocket or guided missile that sustains flight after the burnout of the booster. the rocket engine or cluster of engines contained in such a stage. 1
- noun sustainer a rocket engine that maintains the velocity of a space vehicle after the booster has been jettisoned 0