Tack is the name which is given to all of the equipment which a rider needs to ride a horse. Different horses and different riders will prefer different combinations of this equipment but it is all called tack. Getting a horse ready to ride is often called tacking up. Most tack is leather and needs to be very good quality as it will be used often and will be required to be hard-wearing, as it will be used outdoors and through tough situations, often including rain, mud and other inclement conditions.
The bridle is the leather straps which go around the horse's head and allow the rider to control the horse. The reins come from the bridle and the bridle can be adjusted to pick the head up and lower the head, depending on the individual horse and how much control the rider wants to have. All of the other pieces of tack around the horse's head are generally connected to the bridle in some way.
The bit is the metal piece of tack which goes in the horse's mouth. The idea of it is that it can be used to direct the horse through pressure and never pain. There are many different types of bit and most of them work in different ways to others. The phrase getting the bit between his teeth actually refers to when a horse tenses its mouth to grab the bit tighter, as the bit does not rest on the animal's teeth but on its gums. Some horses do learn to bite down on it with their molars.
The saddle is one of the biggest individual pieces of tack. It is fairly self-explanatory with regards to what it is and what it is used for. Made of leather, a good saddle is vital. They are not cheap, but likewise, it is not worth scrimping on them, for your comfort and safety, and that of your horse, is dependent on having a good saddle.
Blinkers are the eye shields, made of leather or sometimes plastic which restrict the horse's vision, prompting him to look ahead. Not all riders use them and they are commonly seen on racehorses. Riders who use them believe that they make the horse more focussed as they concentrate his vision going forward.
The reins are the means by which the rider has control of the horse. It is absolutely vital that any new rider learns how to hold reins correctly from the start, otherwise the horse may well be confused. By pulling on the reins in different ways, the rider should be able to control all aspects of the horse's movement, including how fast it goes, what style of gait it uses and whether it goes left, right or straight. When combined with other actions, such as use of the stirrup, a rider should have complete control of their mount.
The stirrups are the metal hoops in which the rider puts their feet. They are needed to mount the horse and partly to control it when riding. They are also vital for balance and control of the rider's own body. The length of the stirrups may be adjusted depending on the individual rider and quite how much control they want to have in their feet.
The girth is the strap which reaches under the horse's belly to secure the saddle and the stirrups. It is imperative that it is comfortable for the horse, but tight enough to ensure the rider's safety.