- 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.
Examples from the Web for sustainer
A suffocating silence filled the Sustainer Theater on LSA Anaconda in Iraq.The Names You Don’t Hear: Nearly 200 Women Have Died in Iraq and Afghanistan|Kate Hoit|May 26, 2014|DAILY BEAST
He is not the simple aggregate of all laws, but he is the Author, and Sustainer, and Substance of all laws.Christianity and Greek Philosophy|Benjamin Franklin Cocker
He says also that He is not a creature, but the Sustainer of all things.The Expositor's Bible: The Epistle to the Hebrews|Thomas Charles Edwards
He was raised from the dungeon to be ruler over the land of Egypt, and the preserver and sustainer of his brethren.Notes on the Book of Deuteronomy, Volume II|Charles Henry Mackintosh