Final answer:
The list where processes are kept ready to execute in main memory is called the ready queue, which plays a vital role in process scheduling in operating systems.
Step-by-step explanation:
Processes that are residing in main memory and ready to execute are kept on a list called the ready queue. In the context of operating systems, the ready queue is the collection of processes that have all necessary resources loaded, such as being in the main memory, and are just waiting for CPU time to execute. This is a crucial part of process scheduling, where the operating system decides which process runs at a given time. The scheduler selects processes from this queue based on certain criteria like priority or first-come-first-served, depending on the scheduling algorithm used.