a rope or strap for leading or tying an animal
a band round an animal's head to which a lead may be attached
a U-shaped strap passing behind the neck, holding up the bodice of a woman's dress; = halter neck
archaic a noose for hanging criminals
‘What mercy can you offer him, Antonio?’ ‘A halter gratis; nothing else, for God's sake!’ — Shakespeare
[Old English hælftre]