A pike is a long spear. Pikes were particularly useful at defeating cavalry, as the pike would pierce the enemy's horse before the horse could trample a soldier. The pike, like most polearms is not intended to be thrown. Soldiers using these would probably not call them "pikes". Those seen in Middle-earth used by the Uruk-hai, were about 15 to 20 feet long. Soldiers that use pikes in battle are called pikemen.
Near the pike head it is affixed with metal strips or "cheeks" to hold the head in place. The pike would be unwieldy in close combat. This would mean that the wielder would have to have another hand weapon such as a dagger, mace or small sword if the battle turned into a melee. However, they tried to avoid such unorganized combat as they were at a disadvantage. They had either no shield, or a very small shield that had a strap so they could strap it in their arm.
Most pike tactics would involve the wielder to kneel on one knee and drive the end of the pike into the ground at an angle. This would create a line of pikes impossible to charge at. If the horsemen did charge, they would plow right into a hedge of super sharp spikes consisting of 20 or 30 soldiers, killing the horse and probably the rider. The pikes have their own weakness; they are heavy and hard to turn while holding one. If the battle was on a flat plain, then the cavalry could go around them and come from behind, trampling anyone behind them.