It's a parasitic relationship.
Equine tapeworms are between 1-3 inches in length.
Horses can contract tapeworms from an infected horse, or even a pasture that has been heavily grazed.
Horses, like all animals are vulnerable to parasites including tapeworms, hookworms, ringworms and tics.
If you are talking about the thing that goes over the horses ears and between its eyes, it is called a fly bonnet.
The knobby area on top of a horses' head and between the ears is called the poll.
It's called a "bit"; hence the expression "bit between your teeth".
The joint between the horse's hock and hip is called the Stifle joint.
Horses are just called "horses" unless they are in a group together. When horses get in a group together, they are then called a "herd".
they are called mustangs. they are the American wild horses. Australian wild horses are called brumbys.
A dozen horses is usually called a 'string' of horses.
They are called a herd of horses.
Horses, generally.