The Collaborative International Dictionary of English v.0.48:
Mho \Mho\, n. [Anagram of ohm.] (Elec.) A unit of conductivity, being the reciprocal of the ohm. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
mho n 1: a unit of conductance equal to the reciprocal of an ohm [syn: mho, siemens, reciprocal ohm, S]