Definition of "sustaining"

Tony's face expressed relief, and Nettie sat silent for a moment until the vicar said “It was a generous impulse, but it may have been a momentary one, while in the case of monk and crusader there must have been a sustaining purpose, and possibly a great abnegation, a leaving of lands and possessions.”

1907, Harold Bindloss, chapter 20, in The Dust of Conflict‎

Beginnings are very different from sustainings; the irregular, often violent, and improvised actions of the founder hero must be succeeded by the regular election of leaders according to law.

2012, Alan Ryan, On Politics

[…] eternall life, the end of all our wearisome labours, and all our sustaining hopes.

1641, John Milton, Of Prelatical Episcopacy‎, London: Thomas Underhill, page 24

I turned quick to look for him, and saw him coming towards me, with another gentleman—But I saw no more, my senses forsook me; in spite of Maria’s sustaining arm, I fell motionless on the ground.

1771, Elizabeth Griffith, The History of Lady Barton, London: T. Davies & T. Cadell, Volume 2, Letter 31, p. 21

Sometimes, I had proceeded restlessly from place to place, stopping nowhere; sometimes, I had lingered long in one spot. I had had no purpose, no sustaining soul within me, anywhere.

1849 May – 1850 November, Charles Dickens, chapter 58, in The Personal History of David Copperfield, London: Bradbury & Evans, […], published 1850

They laughed and chattered, and passed each other sustaining bits of chocolate in torn silver paper.

1929, Josephine Tey, chapter 1, in The Man in the Queue‎, New York: Pocket Book, published 1977, page 5

[…] I was thirsty & went to sit in the shade of the tea-terrace. The tea, served impractically in a glass, was refreshing, somehow muddy & more sustaining than tea I am used to.

1988, Alan Hollinghurst, chapter 8, in The Swimming-Pool Library, paperback edition, London: Penguin Books