'densely-populated' originates from the Latin word 'densus,' meaning 'thick' or 'crowded,' and the Latin word 'populus,' meaning 'people.'

'Densus' transformed into the Old French word 'dense,' and 'populus' became 'populate' in English, eventually forming the modern English term 'densely-populated.'

Initially, it meant 'thickly inhabited,' but over time it evolved into its current meaning of 'having a high population density.'