Wiktionary
n. A horse used for bareback riding performances.
Usage examples of "rosinback".
Clover Lee was now essaying every rosinback posture and spin and leap from horse to horse that both her mother and Captain Hotspur had ever done.
Clover Lee did her rosinback act with consummate grace, performing her most spectacular tricks directly in front of the chair of the young, slim, smiling Prince Umberto.
Florian or Colonel Ramrod to excuse them from the next show, and often just minutes before they were due to go on, for fear that the cramps or the diarrhea were about to strike when they were variously on the trapeze, on a rosinback horse, on the tightrope or in one of the wild animal cages.
She was competent and graceful enough on the rosinback, but workmanlike, not sprightly and vivacious.