1. The action of ordaining or announcing authoritatively and publicly; an appointment, a declaration, or a proclamation: "The indiction of the mayor was held at an outdoor ceremony so a large number of people could attend."
2. The decree or proclamation of the Roman Emperors fixing the valuation on which the property-tax was assessed at the beginning of each period of fifteen years; hence, the tax or subsidy paid on the basis of this assessment: "The emperor issued a new indiction in order to increase his revenue which would be used for building monuments."