[noun] [C], [adverb] [not gradable] - (on) a saddle used by women, on which the rider sits with both legs on the same side of the horseThe Queen rode on a sidesaddle/rode sidesaddle when she inspected the soldiers.
SIDESADDLE
Meaning of SIDESADDLE in English
Cambridge English vocab. Кембриджский английский словарь. 2012