Answer: System.
Answer analysis: When subsystems are combined together, the result they form together is usually called a system.
In the context of product development or system design, a system refers to a group of components that are interrelated, interact with each other, and play a specific function together. These component collections can be mechanical structures, electronic structures, component chips, software programs, or other complex functional collections.
Subsystems are part of the system. They can be hardware or software, responsible for implementing one or more specific functions in the system.
When multiple subsystems are combined together according to certain rules or methods, a complete system is formed, which can perform more complex and diverse tasks.
This combination method helps to realize the modular design of the system, making the system easier to develop, maintain and upgrade.
At the same time, by combining different subsystems, different functions can be customized and expanded to meet different application requirements.
Therefore, when subsystems are combined together, the result they form together is called a system.