Boosting in Halo 3 is a technique that allows players to propel themselves and their teammates into the air using a combination of melee attacks and equipment. It is a fundamental skill in the game, allowing players to quickly traverse the maps, gain an advantage in combat, and perform impressive trick jumps.
To boost, players must first sprint towards a teammate and melee them. This will launch the teammate into the air. The player can then jump and melee the teammate again, which will launch the player into the air as well. The player can continue to melee the teammate in mid-air to gain even more height and distance.