'liquefy' originates from Latin, specifically the word 'liquefacere', where 'liquēre' meant 'to be liquid' and 'facere' meant 'to make'.

'liquefacere' changed into Old French (or Medieval French) 'liquéfier' and later entered English as 'liquefy' via Middle French and Early Modern English.

Initially it meant 'to make liquid' (to cause to be liquid), and over time it has retained essentially the same meaning: 'to make or become liquid'.