Cowboy Dictionary - Letter N
Near Side - The left side of a horse. The right side of a horse is the "off" side.
Night Latch - A leather strap (or something similar) attached to a saddle for the rider to use when a horse is bucking.
A rider grabs onto, and pulls on, a night latch when a horse is bucking to help pull themselves deeper into the saddle. A night latch is typically a leather strap, a short piece of rope, or something similar, that has been run through the gullet of the saddle.
You can shop for a night latch here.
Below: A pony ranch bronc rider uses a night latch.