'moderate' originates from Latin, specifically the word 'moderatus,' where 'moderare' meant 'to restrain or control.' 'Income' originates from Middle English, specifically the word 'incomen,' where 'in-' meant 'into' and 'comen' meant 'to come.'

'moderatus' transformed into the Old French word 'moderer,' and eventually became the modern English word 'moderate' through Middle English. 'Incomen' evolved into the modern English word 'income.'

Initially, 'moderate' meant 'restrained or controlled,' and 'income' meant 'money coming in.' Over time, 'moderate-income' evolved to describe a middle-range income level.