|Origin:||laisse, from laissier; LEASE2|
leash1 [countable] especially American English
a piece of rope, leather etc fastened to a dog's collar in order to control it [= lead British English]
on/off a leash
At her side on a leash trotted a small grey dog.
Never leave your dog off the leash outside a store.
to control someone - used humorously:
Marcus keeps you on a short leash, does he?