What is the Full Form of CMOS ?

CMOS - Complementary Metal Oxide Semiconductor

Complementary Metal Oxide Semiconductor is a widely used semiconductor technology used in the transistors. It uses both NMOS (negative polarity) and PMOS (positive polarity) circuits, but only one of the circuit types is on at any given time, due to which it requires less power than chips using just one type of transistor. Since it requires very less power, it is ideal for use in Personal Computers, microprocessors, microcontrollers, and other digital logic circuits.

CMOS is sometimes referred to as complementary-symmetry metal–oxide–semiconductor (COS-MOS). Here the words "complementary-symmetry" refers to the fact that CMOS uses complementary and symmetrical pairs of p-type and n-type metal oxide semiconductor.