sustainer

noun

1. A person or thing that sustains.

   “[…] But thy selfe, hast a sustainer bene Of much affliction in my cause: […]”

   “1724, Aaron Hill and William Bond, The Plain Dealer, No. 36, 24 July, 1724, London: S. Richardson & A. Wilde, p. 296, […] not One in Fifty, of our Men of Fashion, or of Quality, as they call themselves, has an Understanding that is able to go alone. They are forc’d, therefore, to wait ’till they have their Sustainer’s Opinion to lean against, before they dare venture upon the Praise, even of what they are inclinable to think favourably of […]”

   “[Bread] constitutes of itself a complete life sustainer, the gluten, starch and sugar which it contains representing ozotized and hydro-carbonated nutrients, and combining the sustaining powers of the animal and vegetable kingdoms in one product.”

   “What a good lot of people they all were, I was betrayed by their applause and too many pink gins into thinking, the red-jowled sustainers of a great empire and their ladies, quaffers and yarners and players of deck games.”

2. A rocket engine that remains with a spacecraft during its ascent after the separation of the booster engines.
3. (US)A person who makes regular donations, especially to a public radio or television station.
4. (US, obsolete)A radio program without a commercial sponsor.

   “21st time this year a sponsor gave the nod to a sustainer: from now on Let’s Pretend, a CBS sustainer for 13 years, will pretend for Cream of Wheat.”