A jack is a device for lifting heavy objects off the ground by pushing them up from underneath. Jacks are used to raise things a short distance only. They are commonly used to lift one corner of a car off the ground while you change a tyre.
Jack is also a variation of the name John.
Jack Russells are small dogs that are mainly white, with patches of brown or black. They might have smooth or rough coats. They were originally bred for hunting foxes. They are intelligent, energetic, fearless and vocal. If they are left alone or not exercised enough, they can get bored and destructive. They do not make good indoor dogs.
A jackal is a small to medium sized close relative of the dog. They are found in Africa, Asia and some parts of Europe. Jackals normally live together in pairs, although they will sometimes form small packs to hunt. They hunt small to medium animals, and will eat dead animals they find. Like household dogs they will also eat fruit and other plants as well as meat.