I never through I would see anyone referring to the mho in the hobby space... The mho is the inverse of ohm, as conductance is the inverse of resistance.
Mho is literally ohm spelled backwards, but is also referred to as the siemans. There are two symbols used, when referring to it as the mho the resistance symbol (the greek capital Omega) except upside down. When referring to it as the siemans, a capital S is used. The siemans reference is from some German guy's last name, but I don't remember off hand who specifically it was. Strangely, although it is after some guy's name, and the symbol being capital, when spelling out the word itself it is proper to use a lower case s...
Beyond this, there is also susceptance, which is the inverse of reactance, and admittance, the inverse of impedance.
I know these from working with smith charts. That being said, outside of smith charts, I haven't seen them used anywhere in the hobby space, including the more advanced discussions, so you don't have to worry about them to much...
The DB