Definition of "trotter"

Charlie kept telling himself that Eddie Gillespie was the great runner, while he was just a quick trotter.

2013, Stephen Dobyns, Saratoga Bestiary

... empiricism “A lame cripple going along the right road can overtake a trotter if the latter is running along the wrong road. Moreover, the faster the trotter runs, once having lost the path, the further he lags behind the cripple”. […]

2013 October 22, D. Ter Haar, Collected Papers of P.L. Kapitza: Volume 3‎, volume 3, Elsevier, page 174

The Celebrity, by arts unknown, induced Mrs. Judge Short and two other ladies to call at Mohair on a certain afternoon when Mr. Cooke was trying a trotter on the track. The three returned wondering and charmed with Mrs. Cooke; they were sure she had had no hand in the furnishing of that atrocious house.

1897 December (indicated as 1898), Winston Churchill, chapter IV, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., page 58

Finally Napoleon raised his trotter for silence and announced that he had already made all the arrangements.

1945 August 17, George Orwell [pseudonym; Eric Arthur Blair], chapter 6, in Animal Farm […], London: Secker & Warburg

Then you get up on your trotters, but you have a job to stand; / For the landscape 'round you totters and your collar's full of sand.

2004, Charley Hester, Kirby Ross, The True Life Wild West Memoir of a Bush-popping Cow Waddy, page 27

One of these proprietors is a magistrate of Oxfordshire, another a justice of the peace for Berkshire, and Stewart, who was a tailor's trotter, originally, was lately high sherriff [sic] of his county.

1830, William Cobbett, Eleven Lectures on the French and Belgian Revolutions, page 8