'gradually-built' originates from the combination of 'gradually' and 'built'. 'Gradually' comes from the Latin word 'gradualis', meaning 'step by step', and 'built' is the past participle of 'build', which comes from the Old English 'byldan', meaning 'to construct'.

'Gradually' evolved from the Latin 'gradualis' through Old French 'graduel', and 'built' evolved from the Old English 'byldan'.

Initially, 'gradually' meant 'step by step', and 'built' meant 'constructed'. The combined term 'gradually-built' retains these meanings, emphasizing a slow construction process.