From Destinypedia, the Destiny wiki
Control is a Crucible match type.
It is a 6v6 mode where the teams have to take control of three flags scattered across a map, and hold them against enemy attack. Points are scored for holding a flag zone, and scoring kills. The first team to score 20,000 points wins.
Point work as follows:
Map control is the main objective, and teams that do not hold and navigate the map correctly will be set at a disadvantage. Two points minimum are required in order for a team to have a strong point flow to stay in the lead. Novice players and teams will assume that holding one point and out killing the other team will suffice, but this is rarely if ever the case. Trying to hold three points if often considered a poor idea, as it leads to the team being stretched thin, and leaves all three points open to attack. On top of holding down point, map awareness is paramount, knowing routes to move through and cover. Not all maps are equal in layout, and in many cases attempting to flip spawn sides is highly recommended to make full on the better positioning. Heavy Ammo typically spawns near A and C points, so each team is likely to be able to secure one crate at least. Defensive Supers are also quite strong in point defense, and can help make up for a numbers disadvantage.