Glossary:CMOS
CMOS (pronounced "sea-moss") or Complementary Metal Oxide Semiconductor is a class of very low power logic gates. In early PCs the BIOS settings were held in CMOS memory kept alive by a small backup battery, and the term is still sometimes (erroneously) used for this memory, although Flash memory is now universally used. (The backup battery now only keeps the real time clock alive.)