From Longman Dictionary of Contemporary EnglishMIRASMIRAS /ˈmaɪræs, -rəs/ noun [uncountable] (Mortgage Interest Relief at Source) a system used until 2000, in the UK, by which someone who had a mortgage (=money borrowed from a bank etc to buy a house) was allowed to pay less income tax. The borrower was given tax relief (=the right to pay less tax) on the interest that he or she paid on the mortgage, and this reduced the cost of the mortgage payments.From Longman Business DictionaryMIRASMIRAS /ˈmaɪræs/ (also Miras) noun [uncountable] TAX mortgage interest tax relief at source; a system in the UK where people with a MORTGAGE (=loan to buy property) were able to get money back from the tax system. MIRAS stopped from April 2000
