'Megohm' definitions:

Definition of 'megohm'

From: WordNet
noun
A unit of resistance equal to one million ohms

Definition of 'Megohm'

From: GCIDE
  • Megohm \Meg"ohm"\, n. [Mega- + ohm.] (Elec.) One of the larger measures of electrical resistance, amounting to one million ohms. [1913 Webster]