Kickstart is the name given to the bootstrap ROM.
Kickstart contains the code needed to boot the standard Amiga hardware and any Autoconfig expansion hardware. The Kickstart also contains many stock parts of the Amiga's operating system, such as Exec, Intuition and the core of AmigaDOS. This meant that a powered-on Amiga already had a lot of the essential parts of the operating system available. Later versions of the Kickstart contained drivers for IDE and SCSI controllers, PC card ports and various other hardware that came built into Amigas.