'adjustable' originates from the Old French word 'ajuster,' meaning 'to bring into line,' and 'rate' comes from the Latin word 'rata,' meaning 'fixed or reckoned.'

'Adjustable' evolved from the Old French 'ajuster' and 'rate' from the Latin 'rata,' eventually forming the modern English term 'adjustable-rate.'

Initially, 'adjustable' meant 'capable of being adjusted,' and 'rate' meant 'fixed or reckoned.' Over time, 'adjustable-rate' came to specifically refer to financial instruments with variable interest rates.