ostler
noun [ C ] uk/ˈɒs.lər/ us/ˈɑː.slɚ/
（旧时旅店等中）料理骡马的人;马夫
in the past, someone who took care of people's horses when they stopped at an inn (= a place where you can stay for a night while on a journey)
An ostler took the cavalryman's horse. 一个马夫牵走了骑兵的马。