From Longman Business Dictionaryflat-rateˈflat-rate adjective1flat-rate charge/fee/pricing etcCOMMERCE a flat-rate charge etc is always the same and does not change depending on the time spent doing something, the results that are produced etcSome agents charge a flat-rate fee, whether they sell your home or not.Under flat-rate pricing, subscribers pay a fixed monthly fee to stay online as long as they want.2[only before a noun]TAX a flat-rate tax is one, usually on income, where the rate does not change in relation to the amount earned, and where there are no ALLOWANCEs (=income on which tax is not paid)SYNFLAT TAXProposals were put forward to replace individual and corporate income taxes with a flat-rate 13% income tax.flat rateˌflat ˈrateFINANCEBANKING a rate of interest charged on a loan from the moment it is taken out. The loan is paid back in INSTALMENTs (=a series of payments) → rate
