Definition - What does Spin-Up mean?
Techopedia explains Spin-Up
Because spin-up requires a major portion of total power output for a computer or device, engineers have tried to limit the required power and the burden of spin-up on a specific device model. This includes efforts to stagger spin-up, or another process called power up in standby, where a RAID controller might control this process for a given drive or set of drives. Specific manufacturers have also developed proprietary technologies for optimizing spin-up and delivering low-energy solutions for the tech market.