'singleness' originates from Middle English, specifically the word 'singlenes,' where 'single' meant 'one' and '-ness' denoted a state or quality.

'singlenes' transformed into the modern English word 'singleness' through the addition of the suffix '-ness' to 'single.'

Initially, it meant 'the state of being one or alone,' and this meaning has largely remained the same in modern usage.