As hereinafter used in this act, the following words and terms shall have the following meanings, unless the text indicates or requires another or different meaning or intent:
"Base year" means the year 1966.
"Base value" means the value assessed by the commissioner for Class II railroad property in each municipality for the base year. For the purpose of determining base value, "Class II" means the classification established by the act of which this act is amendatory and supplementary.
"Base tax rate" means the general real property tax rate in each municipality for the base year.
"Base tax revenue" means the amount determined for each municipality by applying the base tax rate to the base value.