A double block is when two players are working in together to deflect an attacked ball at the net.
When 2 players jump up and block together. Usually the middle and outside or the middle and setter.
A block is used by a front row player. It is when the other team is hitting the ball from the front row and then the player from your team throws up his/her arms in an attempt to keep the other team from making a kill.
Two players are blocking the ball.
block the ball from crossing to your side of the court
A block in volleyball is when you jump up straight with you hands straight and you block a spike.
Whoever answered this initially was wrong. In indoor volleyball a block does not count as a contact, but in outdoor beach volleyball it DOES count as a contact. This is one of the only incidences in which indoor and outdoor volleyball differ in rules (the only other major difference being that players can cross under the net as long as they aren't interfering with the other teams play). The person blocking is still allowed to hit the ball afterwards for the teams second contact however without it counting as a double hit. I got this from the rules and regulations listed in the FIVB website, which is the international federation for volleyball so it's a rather credible source.
only 5 players play
3. 4 if there is a block