Volleyball is an Olympic team sport in which two teams of 6 active players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules. This article focuses on competitive indoor volleyball; numerous other variations of volleyball have developed, most notably the Olympic spin-off sport beach volleyball.

Play proceeds as follows: a player on one of the teams begins a rally by attempting to serve the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over the net and into the receiving team's court. The receiving team must not let the ball touch their court; they may touch the ball as many as three times, typically using the first two touches to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from touching their court. The rally continues in the same manner, with each team allowed as many as three consecutive touches, until either (1): a team makes a kill, grounding the ball on the opponent's court, thus winning the rally; or (2): a team commits a fault, thus losing the rally. The team that wins the rally is awarded a point, and serves the ball to start the next rally. The complete rules are extensive; a few of the most common faults include:

• causing the ball to touch the ground outside the opponents' court or without first passing over the net;
• catching and throwing the ball;
• double hit: two consecutive contacts with the ball made by the same player;
• four consecutive contacts with the ball made by the same team.

The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body.

A number of consistent techniques have evolved in volleyball, including spiking and blocking (because these plays are made above the top of the net the vertical jump is an athletic skill emphasized in the sport) as well as passing, setting, and specialized player positions and offensive and defensive structures.

Origin of volleyball

On February 9, 1895, in Holyoke, Massachusetts (USA), William G Morgan, a YMCA physical education director, created a new game called Mintonette as a pastime to be played preferably indoors and by any number of players. The game took some of its characteristics from tennis and handball. Another indoor sport, basketball, was catching on in the area, having been invented just ten miles (sixteen kilometers) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport less rough than basketball for older members of the YMCA, while still requiring a bit of athletic effort.

The first rules, written down by William G Morgan, called for a net 6 ft 6 in (1.98 m) high, a 25×50 ft (7.6×15.2 m) court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the opponents' court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve.