Bridle hand

the hand which holds the bridle in riding; the left hand.
See under Bridle.
- Job ii. 10.

See also: Bridle, Hand

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
After that first morning she always had somebody to ride at her bridle hand. Old Doyen, the sculptor, was the first to approach them.
She urged the horse by suddenly leaning forward with her body, at the same time, for an instant, letting the rein slack and touching the neck with her bridle hand. She began to draw away from the man.
I received a cut on my bridle hand and had a sword run through my jacket in the shoulder.