What is "shergar"

Shergar (3 March 1978 – c. February 1983) was an Irish-bred, British-trained racehorse, and winner of the 202nd Epsom Derby (1981) by ten lengths – the longest winning margin in the race's history.

Two years later, on 8 February 1983, he was stolen from the Ballymany Stud, near The Curragh in County Kildare, Ireland by masked gunmen and was never seen again. The incident has been the inspiration for several books, documentaries, and a film.