MOS Technology 65xx refers to a family of 8-bit microprocessors from MOS Technology, based on the Motorola 6800 (introduced ca. 1975). The 65xx family most notably included the 6502, used in several home computers such as the Commodore PET and VIC-20, the Apple II, and the Atari 800.
One popular 6502 based computer, the Commodore 64, used a modified 6502 CPU, the 6510. A British computer that used the 6502 was the BBC Micro, manufactured by Acorn, Ltd.
References
MOS Technology 65xx Wikipedia(Text) CC BY-SA