halter

n.

Also halter-neck.

Style of woman's dress with the top held up by a strap passing round the back of the neck, leaving the back and shoulders bare.

halter

n.

A rope or leather strap put round the head of a horse or a dog for leading or fastening it.

bridle

n.

Part of a horse's harness that goes on its head, including the metal bit for the mouth, the straps and the reins.