The KERNAL is Commodore's name for the ROM resident operating system core in its home computers; from the original PET of 1977, via the strongly related versions used in the successor 8-bit machines VIC-20, C64, Plus/4, C16, and C128, all the way to the completely different OS core in the 16-bit Amiga series. The KERNAL consisted of the OS routines and was user callable via a jump table.

According to early Commodore 'myth' and reported by author Jim Butterfield among others, the word KERNAL is an acronym (or maybe more likely, a backronym) standing for Keyboard Entry Read, Network, And Link, which in fact makes good sense considering its role. There's also, however, a theory that the word got the way it is due to a misspelling of the word kernel by some unknown Commodore employee.