the privy purse
noun /ðə ˌprɪvi ˈpɜːs/
/ðə ˌprɪvi ˈpɜːrs/
[singular]- (in the UK) an amount of money that the government gives to the king or queen to pay his or her private expenses plus some official expensesCultureThe money comes mainly from the income of the the Duchy of Lancaster. The privy purse is separate from the Civil List, which pays for other official expenses of the whole royal family.