What is the name of an aerial apparatus designed to deploy an elevated master stream?

The name of an aerial apparatus designed specifically to deploy an elevated master stream is commonly referred to as a water tower. This type of apparatus is equipped with a platform or a nozzle that allows for high-volume water flow from an elevated position, making it particularly effective in handling large fires or when reaching elevated areas is crucial. Water towers are built with this primary function in mind, offering the capability to cover extensive areas and deliver significant water pressure from above, which is essential in fire suppression efforts.

Other types of aerial apparatus include aerial ladders, which are primarily designed for access and rescue operations rather than for deploying elevated master streams. While quints can serve multiple functions, including the ability to pump water, they may not specialize in the same way that a water tower does. Fire trucks, although vital in firefighting operations, typically do not possess the designated features of an aerial apparatus. The unique design and function of water towers make them the correct choice for this particular question regarding elevated master stream deployment.