Early 20th century; earliest use found in Webster's New International Dictionary of the English Language. From ohm + -age, after e.g. voltage, wattage.
Definition of ohmage in US English:
ohmage
nounˈəʊmɪdʒ
Electricity
Electrical resistance as expressed in ohms.
Origin
Early 20th century; earliest use found in Webster's New International Dictionary of the English Language. From ohm + -age, after e.g. voltage, wattage.