From Longman Business Dictionaryinternal rate of returninˌternal ˌrate of reˈturn (plural internal rates of return) abbreviation IRR [countable, uncountable]ACCOUNTINGFINANCE a measure of the value of an investment, expressed as a percentage and calculated by comparing the profit in a year with the amount that was originally investedThe average internal rate of return for the industry is 6.6%. → return
