CGS stands for 'Centimeter', 'Gram' and 'Second'. CGS system is a group of 3 fundamental quantities to measure length, weight and time. MKS stands for 'Meter', 'Kilogram' and 'Second'. MKS system is also a group of 3 fundamental quantities to measure length, mass and time. MKS is bigger unit than CGS with Meter and Kilogram being used instead of Centimeter and Gram. MKS superseded CGS though CGS is also widely used in branches of astrophysics and by scientists.