In multi-player, the base is an area that the owning team can spawn from. All bases start out as neutral except the two home bases. In Warhawk, the bases also provided vehicle and weapon spawns. In Starhawk however, vehicles now are spawned from structures. Weapons may still be available at bases. They are always useful in any game mode for map control, although they can be more emphasized in some modes, like zones.
To capture any non-home bases, stand near the center (marked by a flag) until the capture bar fills up to your team color. An enemy team player can block a capture by also standing in the radius, and will not fill up for either team until one team kills all the opposition or pushed them out of the capture radius. The more team members standing in the capture radius, the faster it is captured.