The CGS system of units has the centimeter, gram, and second as its base units.  Although the default CGS system does not include units of electricity or magnetism, the electrostatic and electromagnetic systems, which are also based in the centimeter, gram, and second, do.

When used in conjunction with the UseSystem command, the CGS system sets the following units for the given dimensions.

To enter a unit in 2-D Math input, select the unit from the appropriate Units palette. If the unit you want is not there, select $\mathrm{unit}$ and then enter the unit.

When you edit a unit, double brackets appear around it.

$\mathrm{with}\left(\mathrm{Units}\left[\mathrm{Standard}\right]\right)\:$

$\mathrm{Units}\left[\mathrm{UseSystem}\right]\left('\mathrm{CGS}'\right)$

$5\mathrm{Unit}\left(\frac{'\mathrm{kg}''m'}{'s'}\right)$

$5⟦\frac{\mathrm{kg}m}{s}⟧$

$\mathrm{combine}\left(\,'\mathrm{units}'\right)$

$500000⟦\frac{g\mathrm{cm}}{s}⟧$

$\frac{\mathrm{Unit}\left('s'\right)}{}$

$500000⟦\mathrm{dyn}⟧$

$\frac{{\mathrm{Unit}\left('\mathrm{cm}'\right)}^2}{}$

$500000⟦\mathrm{barye}⟧$