Margaret with expression of surprise — maiden showing a lot of resistance

• Insulation tester's unit
• Resistor unit
• Unit of electrical resistance
• A lot of resistance
• A unit of resistance equal to one million ohms
• Large unit of resistance

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of megaohm English)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Megohm \Meg"ohm"\, n. [Mega- + ohm.] (Elec.) One of the larger measures of electrical resistance, amounting to one million ohms.

WordNet Word definitions in WordNet
n. a unit of resistance equal to one million ohms