rider; horseman; jockey
Refers to a person who rides a horse, especially in contexts like horse racing or equestrianism. 騎手 is the most common term for a professional jockey.
He is a famous jockey.
He dreamed of becoming a jockey since he was a child.
The jockey checked the horse's condition before the race.
She keeps up rigorous training aiming to become a jockey.
The jockey mounted the horse looking tense.
騎手 specifically means a jockey in horse racing or equestrian contexts, a much narrower and more technical term than the general ライダー.
旗手 (a flag-bearer) and 騎手 (a jockey) are pronounced identically as きしゅ but refer to completely different roles.
counter for people
Compound of 騎 (ki, 'riding') and 手 (shu, 'person' or 'practitioner'), literally meaning 'riding person'. The reading is on'yomi.