Definition of "ostler"

Mr. Frank Churchill having resolved to go home directly, without waiting at all, and his horse seeming to have got a cold, Tom had been sent off immediately for the Crown chaise, and the ostler had stood out and seen it pass by, the boy going a good pace, and driving very steady.

1815 December (indicated as 1816), [Jane Austen], chapter 8, in Emma: […], volume III, London: […] [Charles Roworth and James Moyes] for John Murray

[A]s the London coaches drove up, which in those early days used to set off from the George, Mr. Foker flung the coffee-room window open, and called the guards and coachmen by their Christian names, too, asking about their respective families, and imitating with great liveliness and accuracy the tooting of the horns as Jem the ostler whipped the horses’ cloths off, and the carriages drove gaily away.

1848 November – 1850 December, William Makepeace Thackeray, The History of Pendennis. […], volumes (please specify |volume=I or II), London: Bradbury and Evans, […], published 1849–1850

Followed by the sun, I left the grounds of the mansion and entered the deserted park, an ostler leading a large and passive work-horse out to the day's labour.

1979, J.G. Ballard, The Unlimited Dream Company, chapter 21