'demographic' originates from Greek, specifically the word 'dēmos,' meaning 'people,' and 'graphia,' meaning 'writing or description.' 'Declining' comes from Latin 'declinare,' meaning 'to bend down or turn aside.'

'Demographic' evolved from the Greek 'dēmos' and 'graphia' through French 'démographique,' while 'declining' transformed from Latin 'declinare' through Old French 'decliner.'

Initially, 'demographic' meant 'pertaining to the study of populations,' and 'declining' meant 'bending down.' Over time, they combined to describe a decrease in population.