Officially, "ST" stands for "Sixteen/Thirty-two", which referred to the external 16-bit bus and internal 32-bit processor of the Motorola 68000 chip.

The Atari ST was a major home computer, based on the Motorola 68000 CPU chip, with a minimum of 512 kilobytes of RAM and a 3½-inch floppy disk drive as a storage medium. It resembled the Apple Macintosh and the Commodore Amiga which were also based on the Motorola 68000.

The ST was mainly a competitor of the Apple Macintosh and the Commodore Amiga.