noun
Specifically refers to the trousers worn for horseback riding, typically tight-fitting from knee to ankle.
乗馬クラブでは、乗馬ズボンの着用が推奨されています。
At the riding club, wearing riding breeches is recommended.
Compound of 乗馬 (じょうば, 'horseback riding') and ズボン ('trousers', from French jupon).